Ultraviolet absorbing polymeric dyes and methods for using the same

ABSTRACT

Water soluble light harvesting multichromophores that have an ultraviolet absorption maximum are provided. In some embodiments, the multichromophores include a conjugated segment including a fused 6-5-6 tricyclic co-monomer and a UV absorbance-modifying co-monomer. The multichromophores may include an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith. In some embodiments, a specific binding member is covalently linked to the multichromophore. Also provided are methods of evaluating a sample for the presence of a target analyte and methods of labelling a target molecule using compositions including the light harvesting multichromophores. Kits and systems for practicing the subject methods are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119 (e), this application claims priority to the filing date of U.S. Provisional Patent Application Ser. No. 62/132,449, filed Mar. 12, 2015, the disclosure of which application is incorporated herein by reference.

INTRODUCTION

Fluorescent dyes are compounds which, when irradiated with light of a wavelength which they absorb, emit light of a (usually) different wavelength. Fluorescent dyes find use in a variety of applications in biochemistry, biology and medicine, e.g. in diagnostic kits, in microscopy or in drug screening. Fluorescent dyes are characterized by a number of parameters allowing a user to select a suitable dye depending on the desired purpose. Parameters of interest include the excitation wavelength maximum, the emission wavelength maximum, the Stokes shift, the extinction coefficient, the fluorescence quantum yield and the fluorescence lifetime. Dyes may be selected according to the application of interest in order to, e.g., allow penetration of exciting radiation into biological samples, to minimize background fluorescence and/or to achieve a high signal-to-noise ratio.

Molecular recognition involves the specific binding of two molecules. Molecules which have binding specificity for a target biomolecule find use in a variety of research and diagnostic applications, such as the labelling and separation of analytes, flow cytometry, in situ hybridization, enzyme-linked immunosorbent assays (ELISAs), western blot analysis, magnetic cell separations and chromatography. Target biomolecules may be detected by labelling with a fluorescent dye.

SUMMARY

Water soluble light harvesting multichromophores that have an ultraviolet absorption maximum are provided. In some embodiments, the multichromophores include a conjugated segment including a fused 6-5-6 tricyclic co-monomer and a UV absorbance-modifying co-monomer. The multichromophores may include an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith. In some embodiments, a specific binding member is covalently linked to the multichromophore. Also provided are methods of evaluating a sample for the presence of a target analyte and methods of labelling a target molecule using compositions including the light harvesting multichromophores. Kits and systems for practicing the subject methods are also provided.

BRIEF DESCRIPTION OF THE FIGURES

It is understood that the drawings, described below, are for illustration purposes only. The drawings are not intended to limit the scope of the present teachings in any way.

FIG. 1 illustrates the fluorescence emission profiles of a variety of polymeric tandem dyes based on an exemplary multichromophore core structure of the present disclosure linked to a variety of different acceptor chromophores.

FIG. 2 illustrates the UV absorption spectra of a variety of multichromophores of interest, MC-1 to MC-5.

DEFINITIONS

Before describing exemplary embodiments in greater detail, the following definitions are set forth to illustrate and define the meaning and scope of the terms used in the description.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Singleton, et al., DICTIONARY OF MICROBIOLOGY AND MOLECULAR BIOLOGY, 2D ED., John Wiley and Sons, New York (1994), and Hale & Markham, THE HARPER COLLINS DICTIONARY OF BIOLOGY, Harper Perennial, N.Y. (1991) provide one of skill with the general meaning of many of the terms used herein. Still, certain terms are defined below for the sake of clarity and ease of reference.

It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. For example, the term “a primer” refers to one or more primers, i.e., a single primer and multiple primers. It is further noted that the claims can be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation.

As used herein, the term “sample” relates to a material or mixture of materials, in some cases in liquid form, containing one or more analytes of interest. In some embodiments, the term as used in its broadest sense, refers to any plant, animal or bacterial material containing cells or producing cellular metabolites, such as, for example, tissue or fluid isolated from an individual (including without limitation plasma, serum, cerebrospinal fluid, lymph, tears, saliva and tissue sections) or from in vitro cell culture constituents, as well as samples from the environment. The term “sample” may also refer to a “biological sample”. As used herein, the term “a biological sample” refers to a whole organism or a subset of its tissues, cells or component parts (e.g. body fluids, including, but not limited to, blood, mucus, lymphatic fluid, synovial fluid, cerebrospinal fluid, saliva, amniotic fluid, amniotic cord blood, urine, vaginal fluid and semen). A “biological sample” can also refer to a homogenate, lysate or extract prepared from a whole organism or a subset of its tissues, cells or component parts, or a fraction or portion thereof, including but not limited to, plasma, serum, spinal fluid, lymph fluid, the external sections of the skin, respiratory, intestinal, and genitourinary tracts, tears, saliva, milk, blood cells, tumors and organs. In certain embodiments, the sample has been removed from an animal or plant. Biological samples may include cells. The term “cells” is used in its conventional sense to refer to the basic structural unit of living organisms, both eukaryotic and prokaryotic, having at least a nucleus and a cell membrane. In certain embodiments, cells include prokaryotic cells, such as from bacteria. In other embodiments, cells include eukaryotic cells, such as cells obtained from biological samples from animals, plants or fungi.

As used herein, the terms “affinity” and “avidity” have the same meaning and may be used interchangeably herein. “Affinity” refers to the strength of binding, increased binding affinity being correlated with a lower Kd.

As used herein, the terms “determining,” “measuring,” and “assessing,” and “assaying” are used interchangeably and include both quantitative and qualitative determinations.

As used herein, the terms “support bound” and “linked to a support” are used interchangeably and refer to a moiety (e.g., a specific binding member) that is linked covalently or non-covalently to a support of interest. Covalent linking may involve the chemical reaction of two compatible functional groups (e.g., two chemoselective functional groups, an electrophile and a nucleophile, etc.) to form a covalent bond between the two moieties of interest (e.g. a support and a specific binding member). In some cases, non-covalent linking may involve specific binding between two moieties of interest (e.g., two affinity moieties such as a hapten and an antibody or a biotin moiety and a streptavidin, etc.). In certain cases, non-covalent linking may involve absorption to a substrate.

As used herein, the term “biomolecule” refers to an organic molecule or macromolecule of a naturally occurring class of molecules, or a derivative thereof. Biomolecule is meant to encompass polypeptides (e.g., a peptide, an antibody or an antibody fragment), polynucleotides, carbohydrates (e.g., sugars) and lipids. In some cases, the biomolecule is a specific binding member (e.g., as described herein).

As used herein, the term “polypeptide” refers to a polymeric form of amino acids of any length, including peptides that range from 2-50 amino acids in length and polypeptides that are greater than 50 amino acids in length. The terms “polypeptide” and “protein” are used interchangeably herein. The term “polypeptide” includes polymers of coded and non-coded amino acids, chemically or biochemically modified or derivatized amino acids, and polypeptides having modified peptide backbones in which the conventional backbone has been replaced with non-naturally occurring or synthetic backbones. A polypeptide may be of any convenient length, e.g., 2 or more amino acids, such as 4 or more amino acids, 10 or more amino acids, 20 or more amino acids, 50 or more amino acids, 100 or more amino acids, 300 or more amino acids, such as up to 500 or 1000 or more amino acids. “Peptides” may be 2 or more amino acids, such as 4 or more amino acids, 10 or more amino acids, 20 or more amino acids, such as up to 50 amino acids. In some embodiments, peptides are between 5 and 30 amino acids in length.

As used herein, the term “isolated” refers to an moiety of interest that is at least 60% free, at least 75% free, at least 90% free, at least 95% free, at least 98% free, and even at least 99% free from other components with which the moiety is associated with prior to purification.

A “plurality” contains at least 2 members. In certain cases, a plurality may have 10 or more, such as 100 or more, 1000 or more, 10,000 or more, 100,000 or more, 10⁶ or more, 10⁷ or more, 10⁸ or more or 10⁹ or more members.

Numeric ranges are inclusive of the numbers defining the range.

The term “separating”, as used herein, refers to physical separation of two elements (e.g., by size or affinity, etc.) as well as degradation of one element, leaving the other intact.

As used herein, the term “specific binding” refers to the ability of a capture agent (or a first member of a specific binding pair) to preferentially bind to a particular analyte (or a second member of a specific binding pair) that is present, e.g., in a homogeneous mixture of different analytes. In some instances, a specific binding interaction will discriminate between desirable and undesirable analytes in a sample with a specificity of 10-fold or more for a desirable analyte over an undesirable analytes, such as 100-fold or more, or 1000-fold or more. In some cases, the affinity between a capture agent and analyte when they are specifically bound in a capture agent/analyte complex is at least 10⁻⁸ M, at least 10⁻⁹ M, such as up to 10⁻¹⁰ M.

The methods described herein include multiple steps. Each step may be performed after a predetermined amount of time has elapsed between steps, as desired. As such, the time between performing each step may be 1 second or more, 10 seconds or more, 30 seconds or more, 60 seconds or more, 5 minutes or more, 10 minutes or more, 60 minutes or more and including 5 hours or more. In certain embodiments, each subsequent step is performed immediately after completion of the previous step. In other embodiments, a step may be performed after an incubation or waiting time after completion of the previous step, e.g., a few minutes to an overnight waiting time.

As used herein, the term “linker” or “linkage” refers to a linking moiety that connects two groups and has a backbone of 100 atoms or less in length. A linker or linkage may be a covalent bond that connects two groups or a chain of between 1 and 100 atoms in length, for example a chain of 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20 or more carbon atoms in length, where the linker may be linear, branched, cyclic or a single atom. In some cases, the linker is a branching linker that refers to a linking moiety that connects three or more groups. In certain cases, one, two, three, four or five or more carbon atoms of a linker backbone may be optionally substituted with a sulfur, nitrogen or oxygen heteroatom. The bonds between backbone atoms may be saturated or unsaturated, and in some cases not more than one, two, or three unsaturated bonds are present in a linker backbone. The linker may include one or more substituent groups, for example with an alkyl, aryl or alkenyl group. A linker may include, without limitations, polyethylene glycol; ethers, thioethers, tertiary amines, alkyls, which may be straight or branched, e.g., methyl, ethyl, n-propyl, 1-methylethyl (iso-propyl), n-butyl, n-pentyl, 1,1-dimethylethyl (t-butyl), and the like. The linker backbone may include a cyclic group, for example, an aryl, a heterocycle or a cycloalkyl group, where 2 or more atoms, e.g., 2, 3 or 4 atoms, of the cyclic group are included in the backbone. A linker may be cleavable or non-cleavable.

As used herein, the terms “polyethylene oxide”, “PEO”, “polyethylene glycol”, “PEG moiety” and “PEG” are used interchangeably and refer to a polymeric group including a chain described by the formula —(CH₂—CH₂—O—)_(n)— or a derivative thereof. In some embodiments, “n” is 5000 or less, such as 1000 or less, 500 or less, 200 or less, 100 or less, 50 or less, 40 or less, 30 or less, 20 or less, 15 or less, such as 3 to 15, or 10 to 15. It is understood that the PEG polymeric group may be of any convenient length and may include a variety of terminal groups and/or further substituent groups, including but not limited to, alkyl, aryl, hydroxyl, amino, acyl, acyloxy, and amido terminal and/or substituent groups. PEG groups that may be adapted for use in the subject multichromophores include those PEGs described by S. Zalipsky in “Functionalized poly(ethylene glycol) for preparation of biologically relevant conjugates”, Bioconjugate Chemistry 1995, 6 (2), 150-165; and by Zhu et al in “Water-Soluble Conjugated Polymers for Imaging, Diagnosis, and Therapy”, Chem. Rev., 2012, 112 (8), pp 4687-4735.

As used herein, the term “alkyl” by itself or as part of another substituent refers to a saturated branched or straight-chain monovalent hydrocarbon radical derived by the removal of one hydrogen atom from a single carbon atom of a parent alkane. Alkyl groups of interest include, but are not limited to, methyl; ethyl, propyls such as propan-1-yl or propan-2-yl; and butyls such as butan-1-yl, butan-2-yl, 2-methyl-propan-1-yl or 2-methyl-propan-2-yl. In some embodiments, an alkyl group includes from 1 to 20 carbon atoms. In some embodiments, an alkyl group includes from 1 to 10 carbon atoms. In certain embodiments, an alkyl group includes from 1 to 6 carbon atoms, such as from 1 to 4 carbon atoms. This term includes, by way of example, linear and branched hydrocarbyl groups such as methyl (CH₃—), ethyl (CH₃CH₂—), n-propyl (CH₃CH₂CH₂—), isopropyl ((CH₃)₂CH—), n-butyl (CH₃CH₂CH₂CH₂—), isobutyl ((CH₃)₂CHCH₂—), sec-butyl ((CH₃)(CH₃CH₂)CH—), t-butyl ((CH₃)₃C—), n-pentyl (CH₃CH₂CH₂CH₂CH₂—), and neopentyl ((CH₃)₃CCH₂—).

The term “substituted alkyl” refers to an alkyl group as defined herein wherein one or more carbon atoms in the alkyl chain have been optionally replaced with a heteroatom such as —O—, —N—, —S—, —S(O)_(n)— (where n is 0 to 2), —NR— (where R is hydrogen or alkyl) and having from 1 to 5 substituents selected from the group consisting of alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, oxo, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclyl, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, —SO-alkyl, —SO-aryl, —SO-heteroaryl, —SO₂-alkyl, —SO₂-aryl, —SO₂— heteroaryl, and —NR^(a)R^(b), wherein R′ and R″ may be the same or different and are chosen from hydrogen, optionally substituted alkyl, cycloalkyl, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl and heterocyclic.

“Alkoxy” refers to the group —O-alkyl, wherein alkyl is as defined herein. Alkoxy includes, by way of example, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, t-butoxy, sec-butoxy, n-pentoxy, and the like. The term “alkoxy” also refers to the groups alkenyl-O—, cycloalkyl-O—, cycloalkenyl-O—, and alkynyl-O—, where alkenyl, cycloalkyl, cycloalkenyl, and alkynyl are as defined herein.

The term “substituted alkoxy” refers to the groups substituted alkyl-O—, substituted alkenyl-O—, substituted cycloalkyl-O—, substituted cycloalkenyl-O—, and substituted alkynyl-O— where substituted alkyl, substituted alkenyl, substituted cycloalkyl, substituted cycloalkenyl and substituted alkynyl are as defined herein.

The terms “Alkynyl” and “alkyne” refer to straight or branched monovalent hydrocarbyl groups having from 2 to 6 carbon atoms and preferably 2 to 3 carbon atoms and having at least 1 and preferably from 1 to 2 sites of triple bond unsaturation. Examples of such alkynyl groups include acetylenyl (—C—CH), and propargyl (—CH₂C≡CH). Unless otherwise indicated, the terms include both substituted and unsubstituted groups.

The term “substituted alkynyl” “substituted alkynyl” refers to an alkynyl group as defined herein having from 1 to 5 substituents, or from 1 to 3 substituents, selected from alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloalkenyl, substituted cycloalkenyl, acyl, acylamino, acyloxy, amino, substituted amino, aminoacyl, aminoacyloxy, oxyaminoacyl, azido, cyano, halogen, hydroxyl, oxo, thioketo, carboxyl, carboxylalkyl, thioaryloxy, thioheteroaryloxy, thioheterocyclooxy, thiol, thioalkoxy, substituted thioalkoxy, aryl, aryloxy, heteroaryl, heteroaryloxy, heterocyclyl, heterocyclooxy, hydroxyamino, alkoxyamino, nitro, —SO-alkyl, —SO-substituted alkyl, —SO-aryl, —SO-heteroaryl, —SO₂-alkyl, —SO₂-substituted alkyl, —SO₂-aryl, and —SO₂-heteroaryl.

“Aryl” by itself or as part of another substituent refers to a monovalent aromatic hydrocarbon radical derived by the removal of one hydrogen atom from a single carbon atom of an aromatic ring system. Aryl groups of interest include, but are not limited to, groups derived from aceanthrylene, acenaphthylene, acephenanthrylene, anthracene, azulene, benzene, chrysene, coronene, fluoranthene, fluorene, hexacene, hexaphene, hexalene, as-indacene, s-indacene, indane, indene, naphthalene, octacene, octaphene, octalene, ovalene, penta-2,4-diene, pentacene, pentalene, pentaphene, perylene, phenalene, phenanthrene, picene, pleiadene, pyrene, pyranthrene, rubicene, triphenylene, trinaphthalene and the like. In certain embodiments, an aryl group includes from 6 to 20 carbon atoms. In certain embodiments, an aryl group includes from 6 to 12 carbon atoms. Examples of an aryl group are phenyl and naphthyl.

“Heteroaryl” by itself or as part of another substituent, refers to a monovalent heteroaromatic radical derived by the removal of one hydrogen atom from a single atom of a heteroaromatic ring system. Heteroaryl groups of interest include, but are not limited to, groups derived from acridine, arsindole, carbazole, β-carboline, chromane, chromene, cinnoline, furan, imidazole, indazole, indole, indoline, indolizine, isobenzofuran, isochromene, isoindole, isoindoline, isoquinoline, isothiazole, isoxazole, naphthyridine, oxadiazole, oxazole, perimidine, phenanthridine, phenanthroline, phenazine, phthalazine, pteridine, purine, pyran, pyrazine, pyrazole, pyridazine, pyridine, pyrimidine, pyrrole, pyrrolizine, quinazoline, quinoline, quinolizine, quinoxaline, tetrazole, thiadiazole, thiazole, triazole, benzotriazole, thiophene, triazole, xanthene, benzodioxole and the like. In certain embodiments, the heteroaryl group is from 5-20 membered heteroaryl. In certain embodiments, the heteroaryl group is from 5-10 membered heteroaryl. In certain embodiments, heteroaryl groups are those derived from thiophene, pyrrole, benzothiophene, benzofuran, indole, pyridine, quinoline, imidazole, oxazole and pyrazine.

The term “alkaryl” or “aralkyl” refers to the groups -alkylene-aryl and substituted alkylene-aryl where alkylene, substituted alkylene and aryl are defined herein.

“Alkylene” refers to divalent aliphatic hydrocarbyl groups preferably having from 1 to 6 and more preferably 1 to 3 carbon atoms that are either straight-chained or branched, and which are optionally interrupted with one or more groups selected from —O—, —NR¹⁰—, —NR¹⁰C(O)—, —C(O)NR¹⁰— and the like. This term includes, by way of example, methylene (—CH₂—), ethylene (—CH₂CH₂—), n-propylene (—CH₂CH₂CH₂—), iso-propylene (—CH₂CH(CH₃)—), (—C(CH₃)₂CH₂CH₂—), (—C(CH₃)₂CH₂C(O)—), (—C(CH₃)₂CH₂C(O)NH—), (—CH(CH₃)CH₂—), and the like. “Substituted alkylene” refers to an alkylene group having from 1 to 3 hydrogens replaced with substituents as described for carbons in the definition of “substituted” below.

“Substituted” refers to a group in which one or more hydrogen atoms are independently replaced with the same or different substituent(s). Substituents of interest include, but are not limited to, alkylenedioxy (such as methylenedioxy), -M, —R⁶⁰, —O—, ═O, —OR⁶⁰, —SR⁶⁰, S—, ═S, —NR⁶⁰R⁶¹, ═NR⁶⁰, —CF₃, —CN, —OCN, —SCN, —NO, —NO₂, ═N₂, —N₃, —S(O)₂O—, —S(O)₂OH, —S(O)₂R⁶⁰, —OS(O)₂O—, —OS(O)₂R⁶⁰, —P(O)(O⁻)₂, —P(O)(OR⁶⁰) (O⁻), —OP(O)(OR⁶⁰)(OR⁶¹), —C(O)R⁶⁰, —C(S)R⁶⁰, —C(O)OR⁶⁰, —C(O)NR⁶⁰R⁶¹, —C(O)O—, —C(S) OR⁶⁰, —NR⁶²C(O)NR⁶⁰R⁶¹, —NR⁶²C(S)NR⁶⁰R⁶¹, —NR⁶²C(NR⁶³)NR⁶⁰R⁶¹ and —C(NR⁶²)NR⁶⁰R⁶¹ where M is halogen; R⁶⁰, R⁶¹, R⁶² and R⁶³ are independently hydrogen, alkyl, substituted alkyl, alkoxy, substituted alkoxy, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl, aryl, substituted aryl, heteroaryl or substituted heteroaryl, or optionally R⁶⁰ and R⁶¹ together with the nitrogen atom to which they are bonded form a cycloheteroalkyl or substituted cycloheteroalkyl ring; and R⁶⁴ and R⁶⁵ are independently hydrogen, alkyl, substituted alkyl, aryl, cycloalkyl, substituted cycloalkyl, cycloheteroalkyl, substituted cycloheteroalkyl, aryl, substituted aryl, heteroaryl or substituted heteroaryl, or optionally R⁶⁴ and R⁶⁵ together with the nitrogen atom to which they are bonded form a cycloheteroalkyl or substituted cycloheteroalkyl ring. In certain embodiments, substituents include -M, —R⁶⁰ ═O, —OR⁶⁰, —SR⁶⁰, —S, ═S, —NR⁶⁰R⁶¹, ═NR⁶⁰, —CF₃, —CN, —OCN, —SCN, —NO, —NO₂, ═N₂, —N₃, —S(O)₂R⁶⁰, —OS(O)₂O⁻, —OS(O)₂R⁶⁰, —P(O)(O⁻)₂, —P(O)(OR⁶⁰)(O⁻), —OP(O)(OR⁶⁰)(OR⁶¹), —C(O)R⁶⁰, —C(S)R⁶⁰, —C(O)OR⁶⁰, —C(O)NR⁶⁰R⁶¹, —C(O)O—, —NR⁶²C(O)NR⁶⁰R⁶¹. In certain embodiments, substituents include -M, —R⁶⁰, ═O, —OR⁶⁰, —SR⁶⁰, —NR⁶⁰R⁶¹, —CF₃, —CN, —NO₂, —S(O)₂R⁶⁰, —P(O)(OR⁶⁰)(O⁻), —OP(O)(OR⁶⁰)(OR⁶¹), —C(O)R⁶⁰, —C(O)OR⁶⁰, —C(O)NR⁶⁰R⁶¹, —C(O)O⁻. In certain embodiments, substituents include -M, —R⁶⁰, ═O, —OR⁶⁰, —SR⁶⁰, —NR⁶⁰R⁶¹, —CF₃, —CN, —NO₂, —S(O)₂R⁶⁰, —OP(O)(OR⁶⁰)(OR⁶¹), —C(O)R⁶⁰, C(O)OR⁶⁰, —C(O)O—, where R⁶⁰, R⁶¹ and R⁶² are as defined above. For example, a substituted group may bear a methylenedioxy substituent or one, two, or three substituents selected from a halogen atom, a (1-4C)alkyl group and a (1-4C)alkoxy group. When the group being substituted is an aryl or heteroaryl group, the substituent(s) (e.g., as described herein) may be referred to as “aryl substituent(s)”.

Other definitions of terms may appear throughout the specification.

DETAILED DESCRIPTION

As summarized above, water soluble light harvesting multichromophores are provided. In some embodiments, the multichromophores include a conjugated segment including a fused 6-5-6 tricyclic co-monomer and a UV absorbance-modifying co-monomer, where the multichromophore has an ultraviolet absorption maximum. The multichromophores may include an acceptor chromophore covalently linked to the multichromophores in energy-receiving proximity therewith. In some embodiments, a specific binding member is covalently linked to the multichromophores. Also provided are methods of evaluating a sample for the presence of a target analyte and methods of labelling a target molecule using compositions including the light harvesting multichromophores. Kits and systems for practicing the subject methods are also provided.

Before the various embodiments are described in greater detail, it is to be understood that the teachings of this disclosure are not limited to the particular embodiments described, and as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present teachings will be limited only by the appended claims.

The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described in any way. While the present teachings are described in conjunction with various embodiments, it is not intended that the present teachings be limited to such embodiments. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present teachings, some exemplary methods and materials are now described.

The citation of any publication is for its disclosure prior to the filing date and should not be construed as an admission that the present claims are not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided can be different from the actual publication dates which can be independently confirmed.

As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which can be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present teachings. Any recited method can be carried out in the order of events recited or in any other order which is logically possible.

All patents and publications, including all sequences disclosed within such patents and publications, referred to herein are expressly incorporated by reference.

In further describing the subject invention, light harvesting multichromophores are described first in greater detail. Next, tandem dyes and conjugates thereof which include the subject multichromophores are described. Then, methods of interest in which compositions including the subject multichromophores find use are reviewed. Systems and kits that may be used in practicing methods of the invention are also described.

Light Harvesting Multichromophores

As summarized above, the present disclosure provides a light harvesting multichromophore that has an ultraviolet absorption maximum. In some embodiments, the multichromophore includes a conjugated segment having: a fused 6-5-6 tricyclic co-monomer; and a UV absorbance-modifying co-monomer; where the multichromophore has an ultraviolet absorption maximum. As used herein, the term “ultraviolet absorption maximum” refers to an absorption maximum wavelength that is in the UV region of the electromagnetic spectrum, e.g., a wavelength of 400 nm or less, such as an absorption maximum wavelength in the range of 10 nm to 400 nm.

As used herein, the terms “light harvesting multichromophore”, “polymeric dye” and “conjugated polymer” are used interchangeably and refer to a conjugated polymer which has a structure capable of harvesting light with a particular absorption maximum wavelength and converting it to emitted light at a longer emission maximum wavelength. In some cases, the light harvesting multichromophore is itself fluorescent. Conjugated polymers (CPs) are characterized by a delocalized electronic structure and may have an effective conjugation length that is substantially shorter than the length of the polymer chain, because the backbone may contain a large number of conjugated segments in close proximity. In some cases, conjugated polymers are efficient for light harvesting and provide for optical amplification via Forster energy transfer to an acceptor.

As used herein the term “unit” refers to a structural subunit of a polymer. The term unit is meant to include monomers, co-monomers, co-blocks, conjugated segments, repeating units, and the like. A “repeating unit” is a subunit of a polymer that is defined by the minimum number of distinct structural features that are required for the unit to be considered monomeric, such that when the unit is repeated n times, the resulting structure describes the polymer or a block thereof. In some cases, the polymer may include two or more different repeating units, e.g., when the polymer is a multiblock polymer, each block may define a distinct repeating unit. In some cases, a repeating unit of the polymer includes a single monomer group. In certain instances, a repeating unit of the polymer includes two or more monomer groups, i.e., co-monomer groups, such as two, three, four or more co-monomer groups. As used herein, the term “co-monomer” or “co-monomer group” refers to a structural unit of a polymer that may itself be part of a repeating unit of the polymer. In some embodiments, the conjugated polymer includes a block copolymer that is composed of blocks of polymerized monomers. In such cases, the block copolymer may be described as having distinct repeating units each corresponding to a distinct co-block of the polymer. In some cases, the polymer is a diblock copolymer that contains two different co-blocks. In such cases, the polymer may be described as including co-blocks, where each co-block may be composed of co-monomers, such as one, two, three or more co-monomers.

As used herein, the term “UV absorbance-modifying co-monomer” refers to a co-monomer which imparts on the multichromophore an absorbance maximum that is shifted to a shorter wavelength that is in the ultraviolet region (e.g., to a wavelength of 400 nm or less) relative to the absorbance maximum of a control multichromophore, e.g., a conjugated polymer in which the UV absorbance-modifying co-monomer is not present in a repeating unit. In some cases, the control multichromophore is a polyfluorene multichromophore. In some cases, the control multichromophore is a polycarbazole multichromophore.

Any convenient light harvesting multichromophores may be adapted to include an absorbance-modifying co-monomer in order to provide a multichromophore having an ultraviolet absorption maximum (e.g., an absorption maximum at a wavelength of 400 nm or less). Light harvesting multichromophores of interest that may be modified to include an absorbance-modifying co-monomer include, but are not limited to, those multichromophores described by Gaylord et al. in US Publication Nos. 20040142344, 20080293164, 20080064042, 20100136702, 20110256549, 20120028828, 20120252986 and 20130190193 and U.S. Pat. Nos. 8,575,303 and 8,802,450, the disclosures of which Publications and Patents are herein incorporated by reference in their entirety; and Gaylord et al., J. Am. Chem. Soc., 2001, 123 (26), pp 6417-6418; Feng et al., Chem. Soc. Rev., 2010, 39, 2411-2419; and Traina et al., J. Am. Chem. Soc., 2011, 133 (32), pp 12600-12607, the disclosures of which are herein incorporated by reference in their entirety.

In some embodiments, the multichromophores includes a plurality of first optically active units forming a conjugated system, having an absorption wavelength (e.g., as described herein) at which the first optically active units absorb light to form an excited state. In certain instances, the multichromophores includes a conjugated polymer segment or an oligomeric structure including bandgap-lowering n-conjugated repeating units.

The subject multichromophores may be water soluble. Any convenient water solubilizing groups may be included in the multichromophore to provide for increased water-solubility. While the increase in solubility may vary, in some instances the increase (as compared to the compound without the WSG(s)) is 2 fold or more, e.g., 5 fold, 10 fold, 25 fold, 50 fold, 100 fold or more. The term “water solubilizing group” (WSG) refers to a group that is well solvated in aqueous environments e.g., under physiological conditions, and that imparts improved water solubility upon the molecules to which it is attached. In some embodiments, a WSG increases the solubility of the multichromophore in a predominantly aqueous solution, as compared to a control multichromophore which lacks the WSG. The water solubilizing groups may be any convenient hydrophilic group that is well solvated in aqueous environments. In some cases, the hydrophilic water solubilizing group is charged, e.g., positively or negatively charged. In certain cases, the hydrophilic water solubilizing group is a neutral hydrophilic group. In some embodiments, the WSG is a hydrophilic polymer, e.g., a polyethylene glycol, a cellulose, a chitosan, or a derivative thereof. Water solubilizing groups of interest include, but are not limited to, carboxylate, phosphonate, phosphate, sulfonate, sulfate, sulfinate, sulfonium, ester, polyethylene glycols (PEG) and modified PEGs, hydroxyl, amine, ammonium, guanidinium, pyridinium, polyamine and sulfonium, polyalcohols, straight chain or cyclic saccharides, primary, secondary, tertiary, or quaternary amines and polyamines, phosphonate groups, phosphinate groups, ascorbate groups, glycols, including, polyethers, —COOM′, —SO₃M′, —PO₃M′, —NR₃ ⁺, Y′, (CH₂CH₂O)_(p)R and mixtures thereof, where Y′ can be any halogen, sulfate, sulfonate, or oxygen containing anion, p can be 1 to 500, each R can be independently H or an alkyl (such as methyl) and M′ can be a cationic counterion or hydrogen, —(CH₂CH₂O)_(y)CH₂CH₂XR^(yy), —(CH₂CH₂O)_(yy)CH₂CH₂X—, —X(CH₂CH₂O)_(y)CH₂CH₂—, glycol, and polyethylene glycol, wherein yy is selected from 1 to 1000, X is selected from O, S, and NR^(ZZ), and R^(ZZ) and R^(YY) are independently selected from H and C₁₋₃ alkyl.

Multiple WSGs may be included at a single location in the subject multichoromophores via a branching linker. In certain embodiments, the branching linker is an aralkyl substitutent, further disubstituted with water solubilizing groups. As such, in some cases, the branching linker group is a substitutent of the multichromophore that connects the multichromophore to two or more water solubilizing groups. In some cases, the incorporation of multiple WSGs via branching linkers imparts a desirable solubility on the multichromophore.

In some embodiments, the multichromophore includes substitutent(s) selected from, an alkyl, an aralkyl and a heterocyclic group, each group further substituted with a include water solubilizing groups hydrophilic polymer group, such as a polyethylglycol (PEG) (e.g., a PEG of 2-20 units).

In some embodiments, the multichromophore is a water soluble light harvesting multichromophore including a conjugated segment including: a fluorene co-monomer; and a UV absorbance-modifying co-monomer; wherein the multichromophore has an ultraviolet absorption maximum. In some instances, the multichromophore is a water soluble light harvesting multichromophore including a conjugated segment including: a carbazole co-monomer; and a UV absorbance-modifying co-monomer; wherein the multichromophore has an ultraviolet absorption maximum. In certain embodiments, the multichromophore has an absorption maximum wavelength of 400 nm or less, such as a wavelength in the range of 10 nm to 400 nm, 100 nm to 400 nm, 200 nm to 400 nm, 300 nm to 400 nm, 300 nm to 390 nm, 300 nm to 380 nm, 300 nm to 370 nm, 300 nm to 360 nm, 300 nm to 350 nm, 300 nm to 340 nm, 300 nm to 330 nm, or 300 nm to 325 nm. In certain embodiments, the multichromophore absorbs only UV light, i.e., only light of 400 nm or less, and does not absorb light at wavelengths of greater than 400 nm. In certain instances, the multichromophore has an absorption maximum wavelength of 300 nm to 400 nm. In some instances, the multichromophore has an absorption maximum wavelength in the range of 300 to 400 nm (such as in the range of 300 nm to 390 nm, 300 nm to 380 nm, 300 nm to 370 nm, 300 nm to 360 nm or 300 nm to 325 nm) and an emission maximum wavelength in the range of 375 to 900 nm (such as in the range of 380 nm to 900 nm, 390 nm to 900 nm, or 400 nm to 900 nm). In certain cases, the multichromophore does not absorb visible light, e.g., no absorption at wavelengths of greater than 400 nm, such as wavelengths of 405 nm or more. In certain instances, the multichromophore has an absorption spectrum where 80% or more of the integrated absorption intensity (i.e., the area under the absorption line), such as 85% or more, 90% or more, 95% or more, 98% or more, or 99% or more, is in the UV region, at wavelengths of 400 nm or less.

The multichromophore may have any convenient length. In some cases, the particular number of monomeric repeating units or segments of the multichromophore may fall within the range of 2 to 500,000, such as 2 to 100,000, 2 to 30,000, 2 to 10,000, 2 to 3,000 or 2 to 1,000 units or segments, or such as 5 to 100,000, 10 to 100,000, 100 to 100,000, 200 to 100,000, or 500 to 50,000 units or segments. In some instances, the particular number of monomeric repeating units or segments of the multichromophore may fall within the range of 2 to 1,000, such as 2 to 500, 2 to 100, 3 to 100, 4 to 100, 5 to 100, 6 to 100, 7 to 100, 8 to 100, 9 to 100 or 10 to 100 units or segments.

The multichromophore may be of any convenient molecular weight (MW). In some cases, the MW of the multichromophore may be expressed as an average molecular weight. the In some instances, the polymeric dye has an average molecular weight of from 500 to 500,000, such as from 1,000 to 100,000, from 2,000 to 100,000, from 10,000 to 100,000 or even an average molecular weight of from 50,000 to 100,000.

In some embodiments, the UV absorbance-modifying co-monomer constitutes 25% or more by molarity of the multichromophore, such as 30% or more, 40% or more, 45% or more, 50% or more, 60% or more, 70% or more, or even more by molarity of the multichromophore. In such cases, the multichromophore may include 5 or more repeating units, such as 10 or more, 20 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 200 or more, 500 or more, 1000 or more, 10,000 or more, or even more repeating units. In such cases, the multichromophore may include 5 or more co-monomer units, such as 10 or more, 20 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more, 200 or more, 500 or more, 1000 or more, 10,000 or more, or even more co-monomer units. In certain embodiments, the UV absorbance-modifying co-monomer constitutes 25% or more by molarity of the multichromophore, such as 30% or more, 40% or more, 45% or more, 50% or more, or even more by molarity of the multichromophore, which includes 5 or more repeating units, such as 10 or more, 20 or more, 30 or more, 40 or more, 50 or more, 60 or more, 70 or more, 80 or more, 90 or more, 100 or more repeating units.

The subject multichromophore may have one or more desirable spectroscopic properties, such as a particular absorption maximum wavelength, a particular emission maximum wavelength, extinction coefficient, quantum yield, and the like. In some embodiments, the multichromophore has an emission maximum wavelength in the range of 300 to 900 nm, such as 350 to 850 nm, 350 to 600 nm, 360 to 500 nm, 370 to 500 nm, 380 to 500 nm, 390 to 500 nm or 400 to 500 nm, where specific examples of emission maxima of interest include, but are not limited to: 395 nm±5 nm, 460 nm±5 nm, 490 nm±5 nm, 550 nm±5 nm, 560 nm±5 nm, 605 nm±5 nm, 650 nm±5 nm, 680 nm±5 nm, 700 nm±5 nm, 805 nm±5 nm. In certain instances, the multichromophore has an emission maximum wavelength selected from 395 nm, 460 nm, 490 nm, 550 nm, 560 nm, 605 nm, 650 nm, 680 nm, 700 nm and 805 nm. In certain instances, the multichromophore has an emission maximum wavelength of 395 nm±5 nm.

In some instances, the multichromophore has an extinction coefficient of 5×10⁵ cm⁻¹M⁻¹ or more, such as 6×10⁵ cm⁻¹M⁻¹ or more, 7×10⁵ cm⁻¹M⁻¹ or more, 8×10⁵ cm⁻¹M⁻¹ or more, 9×10⁵ cm⁻¹M⁻¹ or more, such as 1×10⁶ cm⁻¹M⁻¹ or more, 1.5×10⁶ cm⁻¹M⁻¹ or more, 2×10⁶ cm⁻¹M⁻¹ or more, 2.5×10⁶ cm⁻¹ M⁻¹ or more, 3×10⁶ cm⁻¹ M⁻¹ or more, 4×10⁶ cm⁻¹M⁻¹ or more, 5×10⁶ cm⁻¹M¹ or more, 6×10⁶ cm⁻¹M¹ or more, 7×10⁶ cm⁻¹M⁻¹ or more, or 8×10⁶ cm⁻¹M⁻¹ or more. In such cases, the multichromophore may have 5 or more repeating units, such as 6 or more, 7 or more, 8 or more, 9 or more, 10 or more, or even more repeating units. In some embodiments, the multichromophore has a molar extinction coefficient of 5×10⁵ M⁻¹cm⁻¹ or more. In certain embodiments, the multichromophore has a molar extinction coefficient of 1×10⁶ M⁻¹cm⁻¹ or more.

In some instances, the multichromophore has an extinction coefficient of 40,000 cm⁻¹M⁻¹ per repeating unit or more, such as 45,000 cm⁻¹M⁻¹ per repeating unit or more, 50,000 cm⁻¹M⁻¹ per repeating unit or more, 55,000 cm⁻¹M⁻¹ per repeating unit or more, 60,000 cm⁻¹M⁻¹ per repeating unit or more, 70,000 cm⁻¹M⁻¹ per repeating unit or more, 80,000 cm⁻¹M⁻¹ per repeating unit or more, 90,000 cm⁻¹M⁻¹ per repeating unit or more, 100,000 cm⁻¹ M⁻¹ per repeating unit or more, or even more. In some instances, the 40,000 cm⁻¹M⁻¹ per repeating unit or more described herein is an average extinction coefficient. In certain instances, the repeat unit of the multichromophore may include a single monomer, two co-monomers, or three or more co-monomers. In some instances, the multichromophore has an extinction coefficient of 40,000 cm⁻¹M⁻¹ per co-monomer or more, such as 45,000 cm⁻¹M⁻¹ per co-monomer or more, 50,000 cm⁻¹M⁻¹ per co-monomer or more, 55,000 cm⁻¹M⁻¹ per co-monomer or more, 60,000 cm⁻¹M⁻¹ per co-monomer or more, 70,000 cm⁻¹M⁻¹ per co-monomer or more, 80,000 cm⁻¹M⁻¹ per co-monomer or more, 90,000 cm⁻¹ M⁻¹ per co-monomer or more, 100,000 cm⁻¹ M⁻¹ per co-monomer or more, or even more. In some instances, the 40,000 cm⁻¹M⁻¹ per co-monomer or more is an average extinction coefficient.

In certain cases, the multichromophore does not absorb visible light, e.g., light at greater than 400 nm, such as 405 nm or more. In certain instances, the multichromophore has no significant absorption at wavelengths of greater than 400 nm, e.g., an extinction coefficient at a wavelength of more than (such as 405 nm or more, e.g., 405 nm) of 1×10⁵ cm⁻¹M⁻¹ or less, such as 9×10⁴ cm⁻¹M⁻¹ or less, 8×10⁴ cm⁻¹M⁻¹ or less, 7×10⁴ cm⁻¹ M⁻¹ or less, 6×10⁴ cm⁻¹M⁻¹ or less, 5×10⁴ cm⁻¹M⁻¹ or less, 4×10⁴ cm⁻¹M⁻¹ or less, 3×10⁴ cm⁻¹M⁻¹ or less, 2×10⁴ cm⁻¹M⁻¹ or less, 1×10⁴ cm⁻¹M⁻¹ or less, 5×10³ cm⁻¹M⁻¹ or less, 1×10³ cm⁻¹M⁻¹ or less, or even less.

In certain embodiments, the multichromophore is a polymeric dye having a quantum yield of 0.3 or more, such as 0.35 or more, 0.4 or more, 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more, 0.65 or more, 0.7 or more, or even more. In certain cases, the multichromophore has a quantum yield of 0.4 or more. In certain instances, the polymeric dye has a quantum yield of 0.5 or more.

It is understood that in some cases the subject multichromophores may include co-blocks (e.g., n and m co-blocks). The subject multichromophores may include any convenient linear arrangements of n and m co-blocks of various lengths within the structure of the overall polymer. In addition, the multichromophores may include any convenient arrangements of co-monomers within such n and/or m co-blocks. A variety of polymer synthesis methods may be utilized to prepare co-monomers and co-blocks of interest in the preparation of the subject multichromophores. It is understood that in some cases, the polymerization methods may produce a composition including a population of conjugated polymers that includes some variation with respect to the particular length and/or terminal groups (i.e., end groups) present in each CP of the population. The formulae depicted herein may refer to a single compound or to a population or sub-population of polymeric compounds.

In some instances, the multichromophore is described by formula (I):

where:

F¹ is a fused 6-5-6 tricyclic co-monomer;

each M¹ and M² are each independently a UV absorbance-modifying co-monomer;

b is 1 or 2;

a, c, d, e and f are each independently 0 or 1, wherein a+c+d+f≥1;

L¹ is a linking co-monomer comprising a chemoselective tag —Z¹;

each n is an integer from 1 to 100,000;

each m is 0 or an integer from 1 to 10,000;

p is an integer from 1 to 100,000; and

G¹ and G² are each independently selected from a terminal group, a t conjugated segment, a linker and a linked specific binding member.

In some instances of formula (I), F¹ is a fluorene co-monomer. In some instances of formula (I), F¹ is a carbazole co-monomer. In some cases of formula (I), L¹ is a fluorene co-monomer. In certain embodiments of formula (I), L¹ is a carbazole co-monomer.

In some embodiments of formula (I), b is 1. In certain embodiments of formula (I), b is 2. In some instances of formula (I), a is 0. In some cases of formula (I), c is 0. In certain embodiments of formula (I), d is 0. In certain instances of formula (I), e is 0. In certain cases of formula (I), f is 0. In some embodiments of formula (I), a+c+d+f=1 (i.e., a is 1, c is 1, d is 1 or f is 1). In some embodiments of formula (I), a+c+d+f=2. In some embodiments of formula (I), a+c+d+f=3. In some embodiments of formula (I), a+c+d+f=4. In some embodiments of formula (I), f is 1. In certain embodiments of formula (I), e is 1 and d or f is 1, such that d+e+f=2. In certain instances of formula (I), e is 1 and d and f are each 0.

In certain embodiments of formula (I), e is 0 and d, f and m are each 0. In certain instances, e is 1, d+f≤1 and m≥1. In certain instances, e is 1, d and f and each 0 and m≥1. In certain instances, e is 1; d+f=1 and m≥1. In some cases, d is 1 and f is 0. In some cases, d is 0 and f is 1. In some embodiments of formula (I), n, m and p are selected such that the multichromophore includes 2 to 100,000 repeat units (i.e., monomeric repeat units) in total, where the multichromophore may include a variety of distinct monomeric repeat units. In some instances, when m is 0, p is 1 and n is 2 to 100,000. In some embodiments of formula (I), L¹ is a fluorene co-monomer.

A fused 6-5-6 tricyclic co-monomer is a co-monomer including a tricyclic aromatic group having three fused rings in the configuration 6-5-6, i.e. two benzo ring fused to a central 5 membered ring. The 5-membered ring may be a carbocycle or a heterocycle and may further include a sidechain substituent at the ring atom that is not fused to a benzo ring. In certain instances, the fused 6-5-6 tricyclic co-monomer is described by the following structure:

where:

Z is —C(R′)₂— or —N(R′)—;

each R is independently H or one or more aryl substituents; and

each R¹ is independently selected from an alkyl, a substituted alkyl, an aralkyl, a substituted aralkyl, a PEG moiety and -L¹-Z¹, where L¹ is a linker and Z¹ is a chemoslective tag (e.g., a tag including a chemoslective functional group) or a WSG. As used in any of the formulae described herein, * denotes a site for covalent attachment to the unsaturated backbone of a conjugated polymer or an end group. In some embodiments, when Z is —N(R′)—, the fused 6-5-6 tricyclic co-monomer is a carbazole co-monomer. Any convenient carbazole co-monomers may be utilized in the subject multichromophores. In some embodiments, when Z is —C(R′)₂—, the fused 6-5-6 tricyclic co-monomer is a fluorene co-monomer. Any convenient fluorene co-monomers may be utilized in the subject multichromophores. In certain instances of the fused 6-5-6 tricyclic co-monomer, each R¹ is selected from a benzyl group substituted with one, two or more PEG moieties or an alkyl group substituted with two or more PEG moieties.

A fluorene co-monomer is a co-monomer including an aromatic group having a 9H-fluorene core structure substituted at the 9 position with any convenient sidechain substituent(s). In some cases, the fluorene co-monomer is a 9,9-disubstituted fluorene. The fluorene co-monomer is conjugated to adjacent polymeric backbone groups via any convenient positions of the fluorene core structure, such as any two positions of positions 1-8 (see numbering scheme below). In some embodiments, the fluorene core structure is linked to adjacent groups of the polymer backbone via the 2 and 7 positions. In certain embodiments, the fluorene co-monomer is described by the following structure:

where: each R¹ is independently selected from an alkyl, a substituted alkyl, an aralkyl, a substituted aralkyl, a PEG moiety and -L′-Z′, where L¹ is a linker and Z¹ is a chemoslective tag (e.g., a tag including a chemoslective functional group) or a WSG. In certain instances of the fluorene co-monomer, each R¹ is selected from a benzyl group substituted with one, two or more PEG moieties or an alkyl group substituted with two or more PEG moieties. The Z¹ functional group may find use in covalently linking the multichromophore to an acceptor chromophore (e.g., as described herein). In certain instances, Z¹ includes an amino group for covalently linking to the acceptor chromophore. In certain instances, Z¹ includes an carboxylic acid group, or derivative thereof, for covalently linking to the acceptor chromophore. In certain embodiments, L¹ is a branched linker that links to two or more Z¹ groups (e.g., WSGs). In certain instances, the fluorene co-monomer is further substituted with a R⁵ and/or R⁶ substituent located at one, two or more positions selected from positions 1, 3, 4, 5, 6 and 8, where R⁵ and R⁶ are independently selected from a water solubilizing group (WSG) and an aryl substituent (e.g., as described herein).

In certain instances, the fluorene co-monomer is described by the structure:

where: each R¹ is as defined above; and R⁵ and R⁶ are independently selected from H, a water solubilizing group, or an aryl substituent (e.g., as described herein).

In some instances, the fluorene co-monomer is described by the structure:

where each R² is a alkyl substituted with a water solubilizing group or a branched linker connected to two or more water solubilizing groups (e.g., a PEG-disubstituted benzyl or a PEG substituted alkyl). In certain instances of the fluorene co-monomer, each R² is a benzyl group substituted with one, two or three PEG moieties (e.g., —O(CH₂CH₂O)_(n)R′ where R′ is H or an alkyl and n is 1-20, e.g., 3-16 such as n is 8-16). In certain instances of the fluorene co-monomer, each R² is a benzyl group substituted with one —O(CH₂CH₂O)_(n)R′ group (e.g., at the 2, 3 or 4 position), where R′ is H or an alkyl and n is 1-20, e.g., 3-16 such as n is 8-16. In certain instances of the fluorene co-monomer, each R² is a benzyl group substituted with two —O(CH₂CH₂O)_(n)R′ groups (e.g., at the 2,4-, 3,4- or 3,5-positions), where each R′ is independently H or an alkyl and each n is independently 1-20, e.g., 3-16 such as n is 8-16. In certain instances of the fluorene co-monomer, each R² is a benzyl group substituted with three —O(CH₂CH₂O)_(n)R′ groups (e.g., at the 2,4,6-, 2,4,5- or 3,4,5-positions), where each R′ is independently H or an alkyl and each n is independently 1-20, e.g., 3-16 such as n is 8-16. In certain instances of the fluorene co-monomer, each R² is a lower alkyl group substituted with a trivalent branching group each substituted with two PEG moieties (e.g., a —CO—NR″₂ or —O(CH₂R″)₂ trivalent branching group where each R″ is independently a PEG moiety (e.g., —O(CH₂CH₂O)_(n)R′ where R′ is H or an alkyl and n is 1-20, e.g., 3-16 such as n is 8-16).

In certain embodiments, the fluorene co-monomer is described by the following structure:

where R³ is an alkyl substituted with a water solubilizing group (e.g., a PEG substituted alkyl), and R⁴ is L²-Z² wherein L² is a linker and Z² is a chemoselective tag (e.g., for conjugation to an acceptor chromophore). In some instances, the fluorene co-monomer is described by the structure:

wherein:

R³ is a substituent comprising a water solubilizing group (e.g., as described herein);

R⁴ is L²-Z² wherein L² is a linker and Z² is a chemoselective tag (e.g., for conjugation to an acceptor chromophore); and

R⁵ and R⁶ are independently selected from H, a water solubilizing group and an aryl substituent (e.g., an alkyl, a substituted alkyl, an alkoxy, a substituted alkoxy, a halogen or a nitro). In certain instances of the fluorene co-monomer, R³ is a lower alkyl group substituted with a trivalent branching group each substituted with two PEG moieties (e.g., a —CO—NR″₂ or —O(CH₂R″)₂ trivalent branching group where each R″ is a PEG moiety (e.g., —O(CH₂CH₂O)_(n)R′ where R′ is H or an alkyl and n is 1-20, e.g., 3-16 such as n is 8-16).

Any of the fluorene co-monomers described above may be utilized in the subject multichromophores, e.g., multichromophores of formulae (I)-(IV). In some cases, the multichromophores include, as part of the polymeric backbone, one of the following structures:

where each R³ is independently a water solubilizing group connected via an optional linker, or an optionally substituted alkyl, aralkyl or aryl group; Ar is an optionally substituted aryl or heteroaryl group; and n is an integer from 1 to 100,000. In certain embodiments, each R³ is independently a substituted alkyl group. In certain embodiments, each R³ is independently a substituted aralkyl group. In some cases, each R³ and each Ar are independently substituted (via an optional linker) with a water solubilizing group, an acceptor chromophore, a chemoselective functional group or a specific binding moiety.

As used herein, the terms “chemoselective functional group” and “chemoselective tag” are used interchangeably and refer to a functional group that can selectively react with another compatible functional group to form a covalent bond, in some cases, after optional activation of one of the functional groups. Chemoselective functional groups of interest include, but are not limited to, thiols and maleimide or iodoacetamide, amines and carboxylic acids or active esters thereof, as well as groups that can react with one another via Click chemistry, e.g., azide and alkyne groups (e.g., cyclooctyne groups), as well as hydroxyl, hydrazido, hydrazino, aldehyde, ketone, azido, alkyne, phosphine, epoxide, and the like.

Any convenient linking co-monomers (L¹) may be incorporated into the subject multichromophores to provide for a linking group to which may be attached any convenient moieties of interest. Linking co-monomers of interest include, but are not limited to, a fluorene co-monomer, a phenylenevinylene co-monomer, a phenyleneethynylene co-monomer, a carbazole co-monomer, a C₂-C₁₂ alkyne co-monomer, an arylene-ethynylene co-monomer, a heteroarylene-ethynylene co-monomer, an arylene co-monomer and a heteroarylene co-monomer.

Any convenient chemoselective functional groups may be included in the subject multichromophores (e.g., at the —Z), including, but are not limited to, carboxylic acid, active ester (e.g., NHS or sulfo-NHS ester), amino, hydroxyl, thiol, maleimide, iodoacetyl, hydrazido, hydrazino, aldehyde, ketone, azido, alkyne, phosphine, epoxide, and the like.

In certain cases, the linking co-monomer is a substituted or unsubstituted 1,4-phenyl, a substituted or unsubstituted 1,3-phenyl, a substituted or unsubstituted 4,4′-biphenyl, a substituted or unsubstituted 2,5-pyridyl, and a substituted or unsubstituted 2,6-pyridyl. In some instances, the linking co-monomer is a fluorene co-monomer. In certain instances, the linking co-monomer is a UV absorbance-modifying co-monomer (e.g., as described herein).

Any convenient end groups (e.g., G¹ and G²) may be utilized at the terminals of the subject multichromphores. G¹ and G² groups of interest include, but are not limited to a terminal capping group, a t conjugated segment, a linker and a linked specific binding member. In some embodiments, a terminal capping groups is a monovalent group which is conjugated to the backbone of the multichromophore after polymerization. In certain instances, the terminal capping group is an aryl, a substituted aryl, a heteroaryl, a substituted heteroaryl, an alkyl or a substituted alkyl. In certain cases, the terminal capping group is derived from a monomer used in the method of polymerization, e.g., a terminal group such as a halogen (e.g., Br), a boronic acid or a boronic ester, which is capable of undergoing further conjugation. In some instances, G¹ and/or G² is a π conjugated segment. As used herein, a t conjugated segment refers to any convenient segment of a conjugated polymer to which the multichromophore may be conjugated, i.e., allowing delocalization of pi electron across adjacent units. In certain embodiments, G¹ and/or G² is a linker, such as a linker including a functional group suitable for conjugation to a specific binding moiety. It is understood that linkers located at the G¹ and/or G² positions of the multichromophore may be selected so as to be orthogonal to any other linkers including chemoselective tags that may be present at a sidechain of the multichromophore (e.g., at Z¹). In certain embodiments, an amino functional group or derivative thereof is included at G¹ and/or G² and a carboxylic acid functional group or derivative thereof is included at Z¹. In certain embodiments, an carboxylic acid functional group or derivative thereof is included at G¹ and/or G² and an amino functional group or derivative thereof is included at Z¹.

Any convenient UV absorbance-modifying co-monomers may be incorporated into the subject multichromophores to impart upon the multichromophore a UV absorption maximum. In some embodiments, the UV absorbance-modifying co-monomers has an absorption maximum that is 350 nm or less, such as 340 nm or less, 330 nm or less, 320 nm or less, 310 nm or less, 300 nm or less, 290 nm or less, 280 nm or less, 270 nm or less, 260 nm or less, 250 nm or less, 240 nm or less, 230 nm or less, 220 nm or less, 210 nm or less, or 200 nm or less.

In some embodiments, the UV absorbance-modifying co-monomer is an optionally substituted aryl or heteroaryl co-monomer. In some instances, the UV absorbance-modifying co-monomer is a substituted or unsubstituted phenyl, biphenyl or pyridyl co-monomer. In certain embodiments, the UV absorbance-modifying co-monomer is an optionally substituted aryl or heteroaryl co-monomer selected from substituted or unsubstituted 1,4-phenyl, a substituted or unsubstituted 1,3-phenyl, a substituted or unsubstituted 4,4′-biphenyl, a substituted or unsubstituted 2,5-pyridyl, and a substituted or unsubstituted 2,6-pyridyl. In certain instances, the UV absorbance-modifying co-monomer is an optionally substituted aryl or heteroaryl co-monomer selected from one of the following structures:

where Z²-Z⁵ are each independently CR or N, where at least one Z²-Z⁵ is N; and each R and each R¹¹—R¹⁶ are independently selected from hydrogen, water solubilizing group, halogen, cyano, alkoxy, substituted alkoxy, alkyl and substituted alkyl. In certain embodiments, one and only one of Z²-Z⁵ is N. In certain embodiments, two and only two of Z²-Z⁵ is N. In certain instances, R¹¹, R¹² and R¹⁴ are each H. In some instances, R¹² and R¹⁴ are each H. In some instances, R¹¹ and R¹³ are each H. In some cases, R¹⁵ and R¹⁶ are each H. In some instances, the halogen is fluoro. In certain instances, one and only one of R¹—R¹⁴ is an alkyl or a substituted alkyl, and the other three of R¹¹—R¹⁴ are each H. In certain instances, R¹ and R¹³ are each an alkyl or a substituted alkyl and R¹² and R¹⁴ are each H.

In some cases, the UV absorbance-modifying co-monomer is an optionally substituted aryl or heteroaryl co-monomer selected from one of the following:

where n is 1-20 and R′ is H or lower alkyl. In some embodiments of the substituted aryl or heteroaryl co-monomer structures, n is an integer from 3 to 20. In some embodiments, the multichromophore includes a substituted aryl co-monomer described by the following structure:

where n is 1-20 and R′ is H or lower alkyl. In certain instances, n is 3 to 12. In some embodiments, the multichromophore includes a substituted aryl co-monomer described by the following structure:

where each n is independently 1-20 and each R′ is independently H or lower alkyl. In certain embodiments of the substituted aryl or heteroaryl co-monomer structures shown above, n is 3. In certain instances, R′ is methyl. In certain instances, R′ is hydrogen. In some embodiments, the multichromophore includes a substituted aryl co-monomer described by the following structure:

wherein R¹ and R¹³ are each independently an alkyl or a substituted alkyl, such as a lower alkyl or a substituted lower alkyl (e.g., a substituted methyl, such as trifluoromethyl, difluoromethyl or monofluoromethyl). In some embodiments, the multichromophore includes a substituted aryl co-monomer described by the following structure:

wherein R¹ and R¹² are each independently an alkyl or a substituted alkyl, such as a lower alkyl or a substituted lower alkyl (e.g., a substituted methyl, such as trifluoromethyl, difluoromethyl or monofluoromethyl). In some embodiments, the multichromophore includes a substituted aryl co-monomer described by the following structure:

In some embodiments, the multichromophore includes a substituted aryl co-monomer described by the following structure:

wherein R¹ is an alkyl or a substituted alkyl, such as a lower alkyl or a substituted lower alkyl (e.g., a substituted methyl, such as trifluoromethyl, difluoromethyl or monofluoromethyl). In some embodiments, the multichromophore includes a substituted aryl co-monomer described by the following structure:

Any of the UV absorbance-modifying co-monomers described above may be utilized in the subject multichromophores, e.g., multichromophores of formulae (I)-(IV).

In some embodiments, the multichromophore is described by formula (II):

where F¹, M¹, M², a, b, c, e, L¹, Z¹, p, G¹ and G² are as described for formula (I). In some instances of formula (II), F¹ is a fluorene co-monomer. In certain instances of formula (II), F¹ is a carbazole co-monomer. In some embodiments of formula (II), L¹ is a fluorene co-monomer. In certain embodiments of formula (II), L¹ is a carbazole co-monomer. In certain embodiments, the multichromophore is described by formula (III):

where F¹, M¹, M², a, b, c, n, G¹ and G² are as described for formula (I). In some instances of formula (III), F¹ is a fluorene co-monomer. In certain instances of formula (III), F¹ is a carbazole co-monomer.

In some instances of formulae (II) and (III), b is 1 and a+c≥1. In certain instances of formulae (II) and (III), a+c=1 (e.g., a is 1 and c is 0, or a is 0 and c is 1). In certain embodiments of formulae (II) and (III), a+c=2. In some instances of formulae (II) and (III), G¹ is a terminal group; and G² is a terminal group, a linker or a linked specific binding member. In certain cases, G² is a linked specific binding member. In some cases, G² is a linker, where the linker may include a chemoselective tag.

In some instances, the multichromophore is described by formula (IV):

where F¹, M², b, c, e, f, L¹, Z¹, n, m, p, G¹ and G² are as described for formula (I). In some instances of formula (IV), F¹ is a fluorene co-monomer. In certain instances of formula (IV), F¹ is a carbazole co-monomer.

In some embodiments of formula (IV), b is 1; c is 0 or 1; e and f are each 0 or 1, wherein e+f≥1; G¹ is a terminal group; and G² is a terminal group, a linker or a linked specific binding member. In certain instances of formula (IV), c is 1. In certain cases of formula (IV), c is 0. In certain instances of formula (IV), e is 1. In certain cases of formula (IV), e is 0. In certain instances of formula (IV), f is 1. In certain cases of formula (IV), f is 0. In certain cases, G² is a linked specific binding member. In some cases, G² is a linker, where the linker may include a chemoselective tag. In some embodiments of formula (IV), L¹ is a fluorene co-monomer. In some embodiments of formula (IV), L¹ is a carbazole co-monomer.

In some embodiments, the multichromophore is described by the following structure:

where: each R¹ is independently an alkyl substituted with a WSG, or a branching group further substituted with two or more WSGs; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some instances, G¹ is an aryl end group. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In certain embodiments, each R¹ group is a branching group further substituted with two or more WSGs. In certain instances, the branching group is a substituted aralkyl, such as a substituted benzyl group, which is substituted with two PEG groups.

In some embodiments, the multichromophore is described by the following structure:

where: each R¹ is independently an alkyl substituted with a WSG, or a branching group further substituted with two or more WSGs; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some instances, G¹ is an aryl end group. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In certain embodiments, each R1 group is a branching group further substituted with two or more WSGs. In certain instances, the branching group is a substituted aralkyl, such as a substituted benzyl group, which is substituted with two PEG groups.

In some embodiments, the multichromophore is described by the following structure:

where: each R¹ is independently an alkyl substituted with a WSG, or a branching group further substituted with two or more WSGs; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some instances, G¹ is an aryl end group. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In certain embodiments, each R1 group is a branching group further substituted with two or more WSGs. In certain instances, the branching group is a substituted aralkyl, such as a substituted benzyl group, which is substituted with two PEG groups.

In some embodiments, the multichromophore is described by the following structure:

where each Ak is independently an alkyl; mPEG is a methyl-capped PEG group where each n1 and n2 are independently 3 to 20; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In some embodiments, Ak is a C1-6 alkyl. In certain instances, each n1 is 5 to 15. In certain instances, n2 is 3 to 12, such as 3.

In some embodiments, the multichromophore is described by the following structure:

where mPEG is a methyl-capped PEG group; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH.

In some embodiments, the multichromophore is described by the following structure:

where each Ak is independently an alkyl; mPEG is a methyl-capped PEG group where each n1 and each n2 are independently 3 to 20; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In some embodiments, Ak is a C1-6 alkyl. In certain instances, each n1 is 5 to 15. In certain instances, each n2 is 3 to 12, such as 3.

In some embodiments, the multichromophore is described by the following structure:

where mPEG is a methyl-capped PEG group; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In some cases, it is understood that in any of the multichromophore structures set forth herein, a fluorene co-monomer that is depicted could be replaced with a corresponding carbazole co-monomer in the structure, such as a carbazole co-monomer including a single sidechain group R¹ attached to the N atom of the carbazole co-monomer. Polymeric Tandem Dyes

In some embodiments, the light harvesting multichromophore is a polymeric tandem dye. Polymeric tandem dyes include two covalently linked moieties: a donor light harvesting multichromophore (e.g., as described herein) and an acceptor chromophore. In certain embodiments, the polymeric tandem dye includes: a water soluble light harvesting multichromophore including a conjugated segment including: a fused 6-5-6 tricyclic co-monomer (e.g., as described herein); and a UV absorbance-modifying co-monomer (e.g., as described herein); wherein the multichromophore has an ultraviolet absorption maximum (e.g., as described herein); and an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith. In some instances, the acceptor chromophore is a quencher. In certain instances, the acceptor chromophore is a fluorescent dye. As used herein, the term “acceptor chromophore” refers to a light-absorbing molecule that is capable of receiving or absorbing energy transferred from the multichromophore. In some cases, the acceptor chromophore can either emit as light the energy received from the multichromophore or dissipate the energy as heat. It is understood that, unless otherwise stipulated, in the structures and formulae depicted herein, the label “dye” refers to an “acceptor chromophore”. As used herein, the term “quencher” refers to an acceptor chromophore that absorbs energy from the multichromophore and does not emit light but rather can dissipate the energy as heat.

In some embodiments, the polymeric tandem dye may be excited in the UV region at the absorption maximum wavelength of the donor multichromophore and may emit light at the emission wavelength of the acceptor chromophore. In some cases, the light-harvesting multichromophore can transfer energy to an acceptor chromophore species in energy-receiving proximity. Mechanisms for energy transfer include, for example, resonant energy transfer (e.g., Forster (or fluorescence) resonance energy transfer, FRET), quantum charge exchange (Dexter energy transfer) and the like. In some instances, these energy transfer mechanisms are relatively short range; that is, close proximity of the light harvesting multichromophore system to the acceptor chromophore provides for efficient energy transfer. In some instances, under conditions for efficient energy transfer, amplification of the emission from the acceptor chromophore occurs when the number of individual chromophores in the light harvesting multichromophore system is large; that is, the emission from the signaling chromophore is more intense when the incident light (the “pump light”) is at a wavelength which is absorbed by the light harvesting multichromophore than when the signaling chromophore is directly excited by the pump light.

By “efficient” energy transfer is meant 30% or more of the energy harvested is transferred to the acceptor. When the acceptor chromophore is a fluorescent dye, the term efficient energy transfer refers to a fluorescent quantum yield of 0.3 or more, such as 0.4 or more, 0.5 or more, or even greater. By “amplification” is meant that the signal from the acceptor chromophore is 1.5× or greater when excited by the light harvesting chromophore as compared to direct excitation with incident light of an equivalent intensity. The signal may be measured using any convenient method. In some cases, the 1.5× or greater signal refers to an intensity of emitted light. In certain cases, the 1.5× or greater signal refers to an increased signal to noise ratio. In certain embodiments of the polymeric tandem dye, the acceptor chromophore emission is 1.5 fold greater or more when excited by the multichromophore as compared to direct excitation of the acceptor chromophore with incident light.

In some instances, the polymeric tandem dye has an extinction coefficient of 5×10⁵ cm⁻¹M⁻¹ or more, such as 6×10⁵ cm⁻¹M⁻¹ or more, 7×10⁵ cm⁻¹M⁻¹ or more, 8×10⁵ cm⁻¹M⁻¹ or more, 9×10⁵ cm⁻¹M⁻¹ or more, such as 1×10⁶ cm⁻¹M⁻¹ or more, 1.5×10⁶ cm⁻¹M⁻¹ or more, 2×10⁶ cm⁻¹ M⁻¹ or more, 2.5×10⁶ cm⁻¹ M⁻¹ or more, 3×10⁶ cm⁻¹ M⁻¹ or more, 4×10⁶ cm⁻¹M⁻¹ or more, 5×10⁶ cm⁻¹M⁻¹ or more, 6×10⁶ cm⁻¹M⁻¹ or more, 7×10⁶ cm⁻¹M⁻¹ or more, or 8×10⁶ cm⁻¹M⁻¹ or more. In some embodiments, the polymeric tandem dye has a molar extinction coefficient of 5×10⁵ M⁻¹cm⁻¹ or more. In certain embodiments, the polymeric tandem dye has a molar extinction coefficient of 1×10⁶ M⁻¹cm⁻¹ or more.

In certain embodiments, the polymeric tandem dye has a quantum yield of 0.3 or more, such as 0.35 or more, 0.4 or more, 0.45 or more, 0.5 or more, 0.55 or more, 0.6 or more, 0.65 or more, 0.7 or more, or even more. In certain cases, the polymeric tandem dye has a quantum yield of 0.4 or more. In certain instances, the polymeric tandem dye has a quantum yield of 0.5 or more.

Any convenient fluorescent dyes may be utilized in the polymeric tandem dyes as an acceptor chromophore. The terms “fluorescent dye” and “fluorophore” are used interchangeably herein. In some embodiments, the acceptor chromophore is a cyanine dye, a xanthene dye, a coumarin dye, a thiazine dye or an acridine dye. Fluorescent dyes of interest include, but are not limited to, fluorescein, 6-FAM, rhodamine, Texas Red, tetramethylrhodamine, carboxyrhodamine, carboxyrhodamine 6G, carboxyrhodol, carboxyrhodamine 110, Cascade Blue, Cascade Yellow, coumarin, Cy2, Cy3, Cy3.5, Cy5, Cy5.5, Cy-Chrome, phycoerythrin, PerCP (peridinin chlorophyll-a Protein), PerCP-Cy5.5, JOE (6-carboxy-4′,5′-dichloro-2′,7′-dimethoxyfluorescein), NED, ROX (5-(and-6)-carboxy-X-rhodamine), HEX, Lucifer Yellow, Marina Blue, Oregon Green 488, Oregon Green 500, Oregon Green 514, Alexa Fluor 350, Alexa Fluor 430, Alexa Fluor 488, Alexa Fluor 532, Alexa Fluor 546, Alexa Fluor 568, Alexa Fluor 594, Alexa Fluor 633, Alexa Fluor 647, Alexa Fluor 660, Alexa Fluor 680, Alexa Fluor 700, 7-amino-4-methylcoumarin-3-acetic acid, BODIPY FL, BODIPY FL-Br.sub.2, BODIPY 530/550, BODIPY 558/568, BODIPY 564/570, BODIPY 576/589, BODIPY 581/591, BODIPY 630/650, BODIPY 650/665, BODIPY R6G, BODIPY TMR, BODIPY TR, conjugates thereof, and combinations thereof. Lanthanide chelates of interest include, but are not limited to, europium chelates, terbium chelates and samarium chelates. In some embodiments, the polymeric tandem dye includes a polymeric dye linked to an acceptor fluorophore selected from Cy3, Cy3.5, Cy5, Cy5.5, Cy7, Alexa488, Alexa 647 and Alexa700. In certain embodiments, the polymeric tandem dye includes a polymeric dye linked to an acceptor fluorophore selected from Dyomics dyes (such as DY 431, DY 485XL, DY 500XL, DY 530, DY 610, DY 633, DY 640, DY 651, DY 654, DY 682, DY 700, DY 701, DY 704, DY 730, DY 731, DY 732, DY 734, DY 752, DY 754, DY 778, DY 782, DY 800 or DY 831), Biotium CF 555, Cy 3.5, and diethylamino coumarin.

In some embodiments, the polymeric tandem dye has an absorption maximum wavelength in the range of 300 to 400 nm and an emission maximum wavelength in the range of 375 to 900 nm. In certain embodiments, the polymeric tandem dye includes a water soluble light harvesting multichromophore having a conjugated segment including: a fused 6-5-6 tricyclic co-monomer and a UV absorbance-modifying co-monomer. In some instances, the UV absorbance-modifying co-monomer is present at 25% or more by molarity in the polymeric tandem dye, where the multichromophore is a conjugated polymer including 5 or more monomeric repeat units.

In some instances, the polymeric tandem dye is described by formula (V):

where:

F¹ is a fused 6-5-6 tricyclic co-monomer (e.g., as described herein);

each M¹ and M² are each independently a UV absorbance-modifying co-monomer (e.g., as described herein);

b is 1 or 2;

a, c, d and f are each independently 0 or 1, wherein a+c+d+f≥1;

e is 1 or 2;

L¹ is a linking co-monomer that is linked to the acceptor chromophore —C¹;

n is an integer from 1 to 10,000;

m is an integer from 1 to 10,000;

p is an integer from 1 to 100,000; and

G¹ and G² are each independently selected from a terminal group, a π conjugated segment, a linker and a linked specific binding member. In certain embodiments of formula (V), e is 1. In some instances of formula (V), d+f≤1 (i.e., d is 1 and f is 0 or d is 0 and f is 1) and m≥1. In some instances of formula (V), F¹ is a fluorene co-monomer. In certain instances of formula (V), F¹ is a carbazole co-monomer.

In some embodiments, the polymeric tandem dye is described by formula (VI):

where F¹, M¹, M², a, b, c, e, L¹, C¹, p, G¹ and G² are as described for formula (V). In some instances of formula (VI), F¹ is a fluorene co-monomer. In certain instances of formula (VI), F¹ is a carbazole co-monomer. In some embodiments, the polymeric tandem dye is described by formula (VII):

where F¹, M², b, c, e, f, n, m, L¹, C¹, p, G¹ and G² are as described for formula (V). In some instances of formula (VII), F¹ is a fluorene co-monomer. In certain instances of formula (VII), F¹ is a carbazole co-monomer. In certain instances of formula (VII), b is 1; c is 0 or 1; e is 1; and f is 0 or 1. In some cases of formula (VIII), c is 1. In some embodiments of formula (VIII), c is 0. In some instances of formula (VIII), f is 1. In certain instances of formula (VIII), f is 0. In certain cases of formula (VII), G¹ is a terminal group and G² is a terminal group, a linker or a linked specific binding member. In some instances, G² is a linker that includes a chemoselective tag. In some cases, G² is a linked specific binding member.

Any convenient fluorene co-monomers (e.g., as described herein) may be utilized in the polymeric tandem dyes of formulae (V) to (VII). Any convenient carbazole co-monomers may be utilized in the polymeric tandem dyes of formulae (V) to (VII). Any convenient UV absorbance-modifying co-monomers (e.g., as described herein) may be utilized in the polymeric tandem dyes of formulae (V) to (VII). Any convenient linking co-monomers (e.g., as described herein) may be utilized in the polymeric tandem dyes of formulae (V) to (VII). In certain embodiments of formulae (V) to (VII), L¹ is a fluorene co-monomer. In certain embodiments of formulae (V) to (VII), L¹ is a carbazole co-monomer. In some instances of formulae (V) to (VII), L¹ is described by the structure:

wherein:

R¹ is a substituent including a water solubilizing group (e.g., a PEG substituted alkyl);

R² is L²-Z² wherein L² is a linker and Z² is the acceptor chromophore; and

R³ and R⁴ are independently selected from H, a water solubilizing group, an alkyl, a substituted alkyl, an alkoxy, a substituted alkoxy, a halogen and a nitro. In certain instances, R³ and R⁴ are each hydrogen.

In some embodiments of formula (V) to (VIII), at least one of G¹ and G² is -L³-Z where L³ is a linker (e.g., as described herein) and Z is a specific binding member (e.g., as described herein). In some embodiments of formula (I) to (VIII), at least one of G¹ and G² is -L³-Z where L³ is a linker (e.g., as described herein) and Z is a chemoselective tag (e.g., as described herein). In some instances, Z is selected from carboxylic acid, active ester (e.g., N-hydroxy succinimidyl ester (NHS) or sulfo-NHS), amino, maleimide, iodoacetyl and thiol. In certain embodiments of formula (I) to (VIII), at least one of G¹ and G² is described by the following structure: *—Ar-L-Z

where Ar is a π-conjugated aryl group, L is a linker and Z is a chemoselective tag or a specific binding member. In certain embodiments of formula (I) to (VIII), at least one of G¹ and G² is described by one of the following structures:

wherein:

q is 0 or an integer from 1-12;

L is an optional linker; and

Z is a chemoselective tag or a specific binding member. In certain embodiments of formula (I) to (VIII), at least one L² group is described by the structure:

where q is 0 or an integer from 1-12; L is an optional linker; and Z is a chemoselective tag or a specific binding member. In certain instances, —NH-L-Z includes an amide linkage to the chemoselective tag or specific binding member.

In certain embodiments, Z is a biomolecule. In certain instances, Z is an antibody. In some instances, Z is an antibody fragment or binding derivative thereof. In some cases, the antibody fragment or binding derivative thereof is selected from a Fab fragment, a F(ab′)₂ fragment, a scFv, a diabody and a triabody.

In some embodiments of formulae (V) to (VII), the C¹ is selected from a cyanine dye, a xanthene dye, a coumarin dye, a thiazine dye and an acridine dye, linked to L¹ via an optional linker. In certain cases, the linker is selected from an alkyl, a substituted alkyl, an alkyl-amido, an alkyl-amido-alkyl and a PEG moiety. In certain embodiments of formulae (V) to (VII), the acceptor chromophore C¹ is selected from DY 431, DY 485XL, DY 500XL, DY 610, DY 640, DY 654, DY 682, DY 700, DY 701, DY 704, DY 730, DY 731, DY 732, DY 734, DY 752, DY 778, DY 782, DY 800, DY 831, Biotium CF 555, Cy 3.5 and diethylamino coumarin.

In some embodiments, the polymeric tandem dye is described by the following structure:

where: each R¹ is independently an alkyl substituted with a WSG, or a branching group further substituted with two or more WSGs; R² is L²-Z² wherein L² is a linker and Z² is the acceptor chromophore; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n, m and p are each independently an integer from 1 to 100,000. In some instances, G¹ is an aryl end group. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In certain embodiments, one or more of the R¹ groups is a branching group further substituted with two or more WSGs. In certain instances, the branching group is a substituted aralkyl, such as a substituted benzyl group, which is disubstituted with two PEG groups.

In some embodiments, the multichromophore is described by the following structure:

where: each R¹ is independently an alkyl substituted with a WSG, or a branching group further substituted with two or more WSGs; R² is L²-Z² wherein L² is a linker and Z² is the acceptor chromophore; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n, m and p are each independently an integer from 1 to 100,000. In some instances, G¹ is an aryl end group. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In certain embodiments, one or more of the R¹ groups is a branching group further substituted with two or more WSGs. In certain instances, the branching group is a substituted aralkyl, such as a substituted benzyl group, which is disubstituted with two PEG groups.

In some embodiments, the multichromophore is described by the following structure:

where: each R¹ is independently an alkyl substituted with a WSG, or a branching group further substituted with two or more WSGs; R² is L²-Z² wherein L² is a linker and Z² is the acceptor chromophore; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some instances, G¹ is an aryl end group. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In certain embodiments, one or more of the R¹ groups is a branching group further substituted with two or more WSGs. In certain instances, the branching group is a substituted aralkyl, such as a substituted benzyl group, which is substituted with two PEG groups.

In some embodiments, the multichromophore is described by the following structure:

where each R^(c) is independently selected from an alkyl substituted with a WSG, a branching group further substituted with two or more WSGs, and -Ak-O-mPEG_(n1); each Ak is independently an alkyl; mPEG is a methyl-capped PEG group where each n1 and n2 are independently 3 to 20; R² is L²-Z² wherein L² is a linker and Z² is the acceptor chromophore L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In some embodiments, Ak is a C₁₋₆ alkyl. In some instances, each Ak is —CH₂—. In some cases, each R¹ is -propyl-O-mPEG₁₁. In certain instances, each n1 is 5 to 15. In certain instances, n2 is 3 to 12, such as 3.

In some embodiments, the multichromophore is described by the following structure:

where each Ak is independently an alkyl; mPEG is a methyl-capped PEG group where each n1 and each n2 are independently 3 to 20; wherein L² is a linker and Z² is the acceptor chromophore; L is a linker and Z is a chemoselective tag or a linked specific binding member; G¹ is an end group; and n is an integer from 1 to 100,000. In some cases, G¹ is a phenyl. In certain embodiments, Z is selected from a carboxylic acid, an amino or a maleimide. In certain instances, Z is a linked specific binding member. In some instances, L is an alkyl-carboxylic acid, such as —(CH₂)₃COOH. In some embodiments, Ak is a C1-6 alkyl. In certain instances, each n1 is 5 to 15. In certain instances, each n2 is 3 to 12, such as 3. In some instances, the Ak of the UV-modifying co-monomer is —CH₂—. In some instances, the each Ak of the fluorene co-monomer is —(CH₂)₃—.

It is understood that for any of the structures and formula depicted herein that in some cases of the subject multichromophore the end groups depicted may be located at the opposite ends to those shown, e.g., the end groups G¹ and -Ph-L-Z may be switched.

Labelled Specific Binding Members

Aspects of the present disclosure include labelled specific binding members. A labelled specific binding member is a conjugate of a subject multichromophore (e.g., as described herein) and a specific binding member. The multichromophore may be a polymeric dye. The multichromophore may be polymeric tandem dye. Any of the multichromophores described herein may be conjugated to a specific binding member. The specific binding member and the multichromophore may be conjugated (e.g., covalently linked) to each other via any convenient locations of the multichromophore, via an optional linker.

As used herein, the term “specific binding member” refers to one member of a pair of molecules which have binding specificity for one another. One member of the pair of molecules may have an area on its surface, or a cavity, which specifically binds to an area on the surface of, or a cavity in, the other member of the pair of molecules. Thus the members of the pair have the property of binding specifically to each other to produce a binding complex. In some embodiments, the affinity between specific binding members in a binding complex is characterized by a K_(d) (dissociation constant) of 10⁻⁶ M or less, such as 10⁻⁷ M or less, including 10⁻⁸ M or less, e.g., 10⁻⁹ M or less, 10⁻¹⁰ M or less, 10⁻¹¹ M or less, 10⁻¹² M or less, 10⁻¹³ M or less, 10⁻¹⁴ M or less, including 10⁻¹⁵ M or less. In some embodiments, the specific binding members specifically bind with high avidity. By high avidity is meant that the binding member specifically binds with an apparent affinity characterized by an apparent K_(d) of 10×10⁻⁹ M or less, such as 1×10⁻⁹ M or less, 3×10⁻¹⁰ M or less, 1×10⁻¹⁰ M or less, 3×10⁻¹¹ M or less, 1×10⁻¹¹ M or less, 3×10⁻¹² M or less or 1×10⁻¹² M or less.

As used herein, the term “proteinaceous” refers to a moiety (e.g., a specific binding member) that is composed of amino acid residues. A proteinaceous moiety may be a polypeptide. In some embodiments, the specific binding member is proteinaceous. In certain cases, the proteinaceous specific binding member is an antibody. In certain embodiments, the proteinaceous specific binding member is an antibody fragment, e.g., a binding fragment of an antibody that specific binds to a polymeric dye. As used herein, the terms “antibody” and “antibody molecule” are used interchangeably and refer to a protein consisting of one or more polypeptides substantially encoded by all or part of the recognized immunoglobulin genes. The recognized immunoglobulin genes, for example in humans, include the kappa (κ), lambda (I), and heavy chain genetic loci, which together comprise the myriad variable region genes, and the constant region genes mu (u), delta (d), gamma (g), sigma (e), and alpha (a) which encode the IgM, IgD, IgG, IgE, and IgA isotypes respectively. An immunoglobulin light or heavy chain variable region consists of a “framework” region (FR) interrupted by three hypervariable regions, also called “complementarity determining regions” or “CDRs”. The extent of the framework region and CDRs have been precisely defined (see, “Sequences of Proteins of Immunological Interest,” E. Kabat et al., U.S. Department of Health and Human Services, (1991)). The numbering of all antibody amino acid sequences discussed herein conforms to the Kabat system. The sequences of the framework regions of different light or heavy chains are relatively conserved within a species. The framework region of an antibody, that is the combined framework regions of the constituent light and heavy chains, serves to position and align the CDRs. The CDRs are primarily responsible for binding to an epitope of an antigen.

The term antibody is meant to include full length antibodies and may refer to a natural antibody from any organism, an engineered antibody, or an antibody generated recombinantly for experimental, therapeutic, or other purposes as further defined below. Antibody fragments of interest include, but are not limited to, Fab, Fab′, F(ab′)₂, Fv, scFv, or other antigen-binding subsequences of antibodies, either produced by the modification of whole antibodies or those synthesized de novo using recombinant DNA technologies. Antibodies may be monoclonal or polyclonal and may have other specific activities on cells (e.g., antagonists, agonists, neutralizing, inhibitory, or stimulatory antibodies). It is understood that the antibodies may have additional conservative amino acid substitutions which have substantially no effect on antigen binding or other antibody functions.

In certain embodiments, the specific binding member is an antibody. In certain embodiments, the specific binding member is a Fab fragment, a F(ab′)₂ fragment, a scFv, a diabody or a triabody. In some cases, the specific binding member is a murine antibody or binding fragment thereof. In certain instances, the specific binding member is a recombinant antibody or binding fragment thereof.

In some embodiments, the labelled specific binding member includes: a water soluble light harvesting multichromophore comprising a conjugated segment including: a fluorene co-monomer (e.g., as described herein); and a UV absorbance-modifying co-monomer (e.g., as described herein); where the multichromophore has an ultraviolet absorption maximum; and a specific binding member covalently linked to the multichromophore. In certain embodiments of the labelled specific binding member, the multichromophore has an absorption maximum wavelength in the range of 300 to 400 nm and an emission maximum wavelength in the range of 375 to 900 nm. In some instances of the labelled specific binding member, the UV absorbance-modifying co-monomer includes 25% or more by molarity of the multichromophore; and the multichromophore is a conjugated polymer including 5 or more repeat units.

In certain instances of the labelled specific binding member, the multichromophore has a molar extinction coefficient of 5×10¹ M⁻¹cm⁻¹ or more (e.g., as described herein). In certain cases of the labelled specific binding member, the multichromophore has a quantum yield of 0.3 or more (e.g., as described herein). In some embodiments, the labelled specific binding member further includes an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith, e.g., the multichromophore is a polymeric tandem dye. In certain cases, the acceptor chromophore is a fluorophore. In some embodiments of the labelled specific binding member, the acceptor chromophore emission is 1.5-fold greater or more when excited by the multichromophore as compared to direct excitation of the acceptor chromophore with incident light.

In some instances of the labelled specific binding member, the multichromophore is described by formula (VIII):

wherein:

F¹ is a fused 6-5-6 tricyclic co-monomer;

each M¹ and M² are each independently a UV absorbance-modifying co-monomer;

b is 1 or 2;

a, c, d, e and f are each independently 0 or 1, wherein a+c+d+f≥1;

L¹ is a linking co-monomer that is linked to —Z, wherein Z¹ is a chemoselective tag or an acceptor chromophore;

n is an integer from 1 to 10,000;

m is an integer from 1 to 10,000;

p is an integer from 1 to 100,000; and

G¹ and G² are each independently selected from a terminal group, a t conjugated segment, a linker and a linked specific binding member, wherein at least one of G¹ and G² is a linked specific binding member. In some instances of formula (VIII), F¹ is a fluorene co-monomer. In certain instances of formula (VIII), F¹ is a carbazole co-monomer.

In certain embodiments of formula (VIII), the specific binding member is an antibody. In some instances of formula (VIII), the specific binding member is an antibody fragment or binding derivative thereof. In some cases of formula (VIII), the specific binding member is an antibody fragment or binding derivative thereof that is selected from a Fab fragment, a F(ab′)₂ fragment, a scFv, a diabody and a triabody. In some instances of formula (VIII), the acceptor chromophore is selected from a cyanine dye, a xanthene dye, a coumarin dye, a thiazine dye and an acridine dye. In certain instances of formula (VIII), the acceptor chromophore is selected from DY 431, DY 485XL, DY 500XL, DY 610, DY 640, DY 654, DY 682, DY 700, DY 701, DY 704, DY 730, DY 731, DY 732, DY 734, DY 752, DY 778, DY 782, DY 800, DY 831, Biotium CF 555, Cy 3.5 and diethylamino coumarin.

In some embodiments, the labelled specific binding member is described by the following structure:

where each R¹ is independently an alkyl substituted with a WSG, or a branching group further substituted with two or more WSGs;

the specific binding member is a biomolecule; and

n is an integer from 1 to 100,000. In certain embodiments, each R¹ group is a branching group further substituted with two or more WSGs. In certain instances, the branching group is a substituted aralkyl, such as a substituted benzyl group, which is substituted with two PEG groups.

In certain instances of the fluorene co-monomer of any one of formulae (I)-(VIII), each R¹ or R² sidechain group is a benzyl group substituted with one, two or three PEG moieties (e.g., —O(CH₂CH₂O)_(n)R′ where R′ is H or an alkyl and n is 1-20, e.g., 3-16 such as n is 8-16). In certain instances of the fluorene co-monomer of any one of formulae (III)-(XII), each R¹ or R² sidechain group is a benzyl group substituted with one —O(CH₂CH₂O)_(n)R′ group (e.g., at the 2, 3 or 4 position), where R′ is H or an alkyl and n is 1-20, e.g., 3-16 such as n is 8-16. In certain instances of fluorene co-monomer of any one of formulae (II)-(XII), each R¹ or R² sidechain group is a benzyl group substituted with two —O(CH₂CH₂O)_(n)R′ groups (e.g., at the 2,4-, 3,4- or 3,5-positions), where each R′ is independently H or an alkyl and each n is independently 1-20, e.g., 3-16 such as n is 8-16. In certain instances of the fluorene co-monomer of any one of formulae (II)-(XII), each R¹ or R² sidechain group is a benzyl group substituted with three —O(CH₂CH₂O)_(n)R′ groups (e.g., at the 2,4,6-, 2,4,5- or 3,4,5-positions), where each R′ is independently H or an alkyl and each n is independently 1-20, e.g., 3-16 such as n is 8-16. In certain instances of the fluorene co-monomer of any one of formulae (I)-(VIII), each R¹ or R² sidechain group is a lower alkyl group substituted with a trivalent branching group each substituted with two PEG moieties (e.g., a —CO—NR″₂ or —O(CH₂R″)₂ trivalent branching group where each R″ is independently a PEG moiety (e.g., —O(CH₂CH₂O)_(n)R′ where R′ is H or an alkyl and n is 1-20, e.g., 3-16 such as n is 8-16).

It is understood that the polymeric tandem dye of any one of formulae (I) to (VIII) can alternatively be represented by a formula which indicates what the mol % values for each co-monomer is in the polymer. For example, in some cases, any one of Formulae (I) to (VIII) can be represented by one of the following formula: G¹-(M¹)_(v)(F¹)_(x)(M²)_(y)(L¹)_(z)-G² G¹-(M¹)_(v)(F¹)_(x)(M²)_(y)G² G¹-(F¹)_(x)(M²)_(y)(L¹)_(z)-G² G¹-(F¹)_(x)(M²)_(y)-G²

where v, x, y and z are the mol % values of the co-monomers in the conjugated polymer and L¹ can be linked to C¹ or Z¹ (e.g., as described herein). In some instances of the formulae, v is 1 mol % or more, such as 5 mol % or more, 10 mol % or more, 15 mol % or more, 20 mol % or more, or 25 mol % or more. In some instances of the formulae, v is 25 mol % or less, such as 20 mol % or less, 15 mol % or less, 10 mol % or less, 8 mol % or less, 6 mol % or less, 5 mol % or less, 2 mol % or less, 1 mol % or less, or even less. In some instances of the formulae, x is 1 mol % or more, such as 2 mol % or more, 3 mol % or more, 4 mol % or more, 5 mol % or more, 10 mol % or more, 15 mol % or more, 20 mol % or more, 25 mol % or more, 30 mol % or more, 35 mol % or more, 40 mol % or more, 45 mol % or more, 50 mol % or more, or even more. In certain instances of the formulae, x ranges from 1 mol % to 50 mol %, such as from 5 mol % to 25 mol % or from 10 mol % to 25 mol %; or such as from 5 mol % to 25 mol % or from 10 mol % to 25 mol %; or such as from 1 mol % to 25 mol %, from 1 mol % to 10 mol %, or from 1 mol % to 5 mol %. In some instances of the formulae, z is 10 mol % or more, such as 15 mol % or more, 20 mol % or more, 25 mol % or more, 30 mol % or more, 35 mol % or more, 40 mol % or more, 45 mol % or more, 50 mol % or more, or even more. In some instances of the formulae, z is 25 mol % or less, such as 20 mol % or less, 15 mol % or less, 10 mol % or less, 8 mol % or less, 6 mol % or less, 5 mol % or less, 2 mol % or less, 1 mol % or less, or even less. In some instances of the formulae, y is 1 mol % or more, such as 5 mol % or more, 10 mol % or more, 15 mol % or more, 20 mol % or more, or 25 mol % or more. In some instances of the formulae, y is 25 mol % or less, such as 20 mol % or less, 15 mol % or less, 10 mol % or less, 8 mol % or less, 6 mol % or less, 5 mol % or less, 2 mol % or less, 1 mol % or less, or even less.

It is understood that for any of the structures and formula depicted herein that in some cases of the subject polymeric dyes the end or terminal groups depicted may be located at the opposite ends to those shown, e.g., the end groups may be switched. In some embodiments of the multichromophores described herein (e.g., formulae (I)-(VIII), at least one end group (e.g., L, L², G¹, G², L-Z) is selected from one of the following structures 1-33:

*=site for covalent attachment to unsaturated backbone; wherein R′ is independently H, halogen, C₁-C₁₂ alkyl, (C₁-C₂ alkyl)NH₂, C₂-C₁₂ alkene, C₂-C₁₂ alkyne, C₃-C₁₂cycloalkyl, C₁-C₂ haloalkyl, C₂-C₁₈(hetero)aryl, C₂-C₁₈(hetero)arylamino, —[CH₂—CH₂]_(r′)—Z¹, or (C₁-C₁₂)alkoxy-X; and wherein Z¹ is —OH or —COOH; X¹ is —NH₂, —NHCOOH, —NHCOOC(CH₃)₃, —NHCO(C3-C12)cycloalkyl(C1-C4)alkyl-N-maleimide; or —NHCO[CH₂—CH₂—O]_(s), (CH₂)_(s′)NH₂; r′ is an integer from 1 to 20; and each s′ is independently an integer from 1 to 20, (CH₂)₃(OCH₂CH₂)_(x′)OCH₃ where x″ is independently an integer from 0 to 50, or a benzyl optionally substituted with one or more halogen, hydroxyl, C₁-C₁₂ alkoxy, or (OCH₂CH₂)_(y′)CH₃ where each y″ is independently an integer from 0 to 50 and R′ is different from R; wherein k is 2, 4, 8, 12 or 24; wherein R¹⁵ is selected from groups I-u having the structure:

*=site for covalent attachment to backbone.

In some embodiments of the multichromophores described herein (e.g., formulae (I)-(VIII), at least one end group (e.g., L, L², G¹, G², L-Z) is selected from one of the following structures:

where r is 0 or an integer from 1-50 (e.g., 1-20); k is 0 or an integer from 1-50 (e.g., 1-20); R¹ is as defined for any of the fluorene co-monomers described herein; and R¹⁶ is selected from H, OH, NH₂, —NH(CH₂)r-NH₂, and —NH(CH₂)_(r)COOH. Methods

As summarized above, aspects of the invention include methods of evaluating a sample for the presence of a target analyte. In some embodiments, the method includes: (a) contacting the sample with a polymeric dye conjugate that specifically binds the target analyte to produce a labelling composition contacted sample, where the polymeric dye conjugate includes: (i) a water soluble light harvesting multichromophore (e.g., as described herein) including a conjugated segment including: a fused 6-5-6 tricyclic co-monomer (e.g., as described herein); and a UV absorbance-modifying co-monomer (e.g., as described herein); where the multichromophore has an ultraviolet absorption maximum; and (ii) a specific binding member (e.g., as described herein); and (b) assaying the labelling composition contacted sample for the presence of a polymeric dye conjugate-target analyte binding complex to evaluate whether the target analyte is present in the sample.

Any convenient method may be used to contact the sample with a polymeric dye conjugate that specifically binds to the target analyte to produce the labelling composition contacted sample. As used herein, the terms “polymeric dye conjugate” and “labelled specific binding member” are used interchangeably. In some instances, the sample is contacted with the polymeric dye conjugate under conditions in which the specific binding member specifically binds to the target analyte, if present. For specific binding of the specific binding member of the conjugate with the target analyte, an appropriate solution may be used that maintains the biological activity of the components of the sample and the specific binding member. The solution may be a balanced salt solution, e.g., normal saline, PBS, Hank's balanced salt solution, etc., conveniently supplemented with fetal calf serum, human platelet lysate or other factors, in conjunction with an acceptable buffer at low concentration, such as from 5-25 mM. Convenient buffers include HEPES, phosphate buffers, lactate buffers, etc. Various media are commercially available and may be used according to the nature of the target analyte, including dMEM, HBSS, dPBS, RPMI, Iscove's medium, etc., in some cases supplemented with fetal calf serum or human platelet lysate. The final components of the solution may be selected depending on the components of the sample which are included.

The temperature at which specific binding of the specific binding member of the conjugate to the target analyte takes place may vary, and in some instances may range from 5° C. to 50° C., such as from 10° C. to 40° C., 15° C. to 40° C., 20° C. to 40° C., e.g., 20° C., 25° C., 30° C., 35° C. or 37° C. (e.g., as described above). In some instances, the temperature at which specific binding takes place is selected to be compatible with the biological activity of the specific binding member and/or the target analyte. In certain instances, the temperature is 25° C., 30° C., 35° C. or 37° C. In certain cases, the specific binding member is an antibody or fragment thereof and the temperature at which specific binding takes place is room temperature (e.g., 25° C.), 30° C., 35° C. or 37° C. Any convenient incubation time for specific binding may be selected to allow for the formation of a desirable amount of binding complex, and in some instances, may be 1 minute (min) or more, such as 2 min or more, 10 min or more, 30 min or more, 1 hour or more, 2 hours or more, or even 6 hours or more.

Any convenient specific binding members may be utilized in the conjugate. Specific binding members of interest include, but are not limited to, those agents that specifically bind cell surface proteins of a variety of cell types, including but not limited to, stem cells, e.g., pluripotent stem cells, hematopoietic stem cells, T cells, T regulator cells, dendritic cells, B Cells, e.g., memory B cells, antigen specific B cells, granulocytes, leukemia cells, lymphoma cells, virus cells (e.g., HIV cells) NK cells, macrophages, monocytes, fibroblasts, epithelial cells, endothelial cells, and erythroid cells. Target cells of interest include cells that have a convenient cell surface marker or antigen that may be captured by a convenient specific binding member conjugate. In some embodiments, the target cell is selected from HIV containing cell, a Treg cell, an antigen-specific T-cell populations, tumor cells or hematopoetic progenitor cells (CD34+) from whole blood, bone marrow or cord blood. Any convenient cell surface proteins or cell markers may be targeted for specific binding to polymeric dye conjugates in the subject methods. In some embodiments, the target cell includes a cell surface marker selected from a cell receptor and a cell surface antigen. In some cases, the target cell may include a cell surface antigen such as CD11b, CD123, CD14, CD15, CD16, CD19, CD193, CD2, CD25, CD27, CD3, CD335, CD36, CD4, CD43, CD45RO, CD56, CD61, CD7, CD8, CD34, CD1c, CD23, CD304, CD235a, T cell receptor alpha/beta, T cell receptor gamma/delta, CD253, CD95, CD20, CD105, CD117, CD120b, Notch4, Lgr5 (N-Terminal), SSEA-3, TRA-1-60 Antigen, Disialoganglioside GD2 and CD71.

Any convenient targets may be selected for evaluation utilizing the subject methods. Targets of interest include, but are not limited to, a nucleic acid, such as an RNA, DNA, PNA, CNA, HNA, LNA or ANA molecule, a protein, such as a fusion protein, a modified protein, such as a phosphorylated, glycosylated, ubiquitinated, SUMOylated, or acetylated protein, or an antibody, a peptide, an aggregated biomolecule, a cell, a small molecule, a vitamin and a drug molecule. As used herein, the term “a target protein” refers to all members of the target family, and fragments thereof. The target protein may be any protein of interest, such as a therapeutic or diagnostic target, including but not limited to: hormones, growth factors, receptors, enzymes, cytokines, osteoinductive factors, colony stimulating factors and immunoglobulins. The term “target protein” is intended to include recombinant and synthetic molecules, which can be prepared using any convenient recombinant expression methods or using any convenient synthetic methods, or purchased commercially. In some embodiments, the polymeric dye conjugates include an antibody or antibody fragment. Any convenient target analyte that specifically binds an antibody or antibody fragment of interest may be targeted in the subject methods.

In some embodiments, the target analyte is associated with a cell. In certain instances, the target analyte is a cell surface marker of the cell. In certain cases, the cell surface marker is selected from a cell receptor and a cell surface antigen. In some instances, the target analyte is an intracellular target, and the method further includes lysing the cell.

In some embodiments, the sample may include a heterogeneous cell population from which target cells are isolated. In some instances, the sample includes peripheral whole blood, peripheral whole blood in which erythrocytes have been lysed prior to cell isolation, cord blood, bone marrow, density gradient-purified peripheral blood mononuclear cells or homogenized tissue. In some cases, the sample includes hematopoetic progenitor cells (e.g., CD34+ cells) in whole blood, bone marrow or cord blood. In certain embodiments, the sample includes tumor cells in peripheral blood. In certain instances, the sample is a sample including (or suspected of including) viral cells (e.g., HIV).

The labelled specific binding members find use in the subject methods, e.g., for labeling a target cell, particle, target or analyte with a polymeric dye or polymeric tandem dye. For example, labelled specific binding members find use in labeling cells to be processed (e.g., detected, analyzed, and/or sorted) in a flow cytometer. The labelled specific binding members may include antibodies that specifically bind to, e.g., cell surface proteins of a variety of cell types (e.g., as described herein). The labelled specific binding members may be used to investigate a variety of biological (e.g., cellular) properties or processes such as cell cycle, cell proliferation, cell differentiation, DNA repair, T cell signaling, apoptosis, cell surface protein expression and/or presentation, and so forth. labelled specific binding members may be used in any application that includes (or may include) antibody-mediated labeling of a cell, particle or analyte.

In some embodiments, the polymeric dye conjugate includes a polymeric tandem dye (e.g., as described herein). As such, in some embodiments, the polymeric dye conjugate further includes an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith. In certain embodiments, the conjugate is described by formula (VII):

where:

F¹ is a fused 6-5-6 tricyclic co-monomer;

each M¹ and M² are each independently a UV absorbance-modifying co-monomer;

b is 1 or 2;

a, c, d, e and f are each independently 0 or 1, wherein a+c+d+f≥1;

L¹ is a linking co-monomer that is linked to —Z, wherein Z¹ is a chemoselective tag or an acceptor chromophore;

n is an integer from 1 to 10,000;

m is an integer from 1 to 10,000;

p is an integer from 1 to 100,000; and

G¹ and G² are each independently selected from a terminal group, a t conjugated segment, a linker and a linked specific binding member, wherein at least one of G¹ and G² is a linked specific binding member. In some instances of formula (IX), F¹ is a fluorene co-monomer. In certain instances of formula (IX), F¹ is a carbazole co-monomer.

Once the sample has been contacted with the polymeric dye conjugate, any convenient methods may be utilized in assaying the labelling composition contacted sample that is produced for the presence of a polymeric dye conjugate-target analyte binding complex. The polymeric dye conjugate-target analyte binding complex is the binding complex that is produced upon specific binding of the specific binding member of the conjugate to the target analyte, if present. Assaying the labelling composition contacted sample may include detecting a fluorescent signal from the binding complex, if present. In some cases, the assaying includes a separating step where the target analyte, if present, is separated from the sample. A variety of methods may be utilized to separate a target analyte from a sample, e.g., via immobilization on a support. Assay methods of interest include, but are not limited to, any convenient methods and assay formats where pairs of specific binding members such as avidin-biotin or hapten-anti-hapten antibodies find use, are of interest. Methods and assay formats of interest that may be adapted for use with the subject compositions include, but are not limited to, flow cytometry methods, in-situ hybridization methods, enzyme-linked immunosorbent assays (ELISAs), western blot analysis, magnetic cell separation assays and fluorochrome purification chromatography.

In certain embodiments, the method further includes contacting the sample with a second specific binding member that specifically binds the target analyte. In certain instances, the second specific binding member is support bound. Any convenient supports may be utilized to immobilize a component of the subject methods (e.g., a second specific binding member). In certain instances, the support is a particle, such as a magnetic particle. In some instances, the second specific binding member and the polymeric dye conjugate produce a sandwich complex that may be isolated and detected, if present, using any convenient methods. In some embodiments, the method further includes flow cytometrically analyzing the polymeric dye conjugate-target analyte binding complex, i.e., a fluorescently labelled target analyte. Assaying for the presence of a polymeric dye conjugate-target analyte binding complex may provide assay results (e.g., qualitative or quantitative assay data) which can be used to evaluate whether the target analyte is present in the sample.

Any convenient supports may be utilized in the subject methods. Supports of interest include, but are not limited to: solid substrates, where the substrate can have a variety of configurations, e.g., a sheet, bead, or other structure, such as a plate with wells; beads, polymers, particle, a fibrous mesh, hydrogels, porous matrix, a pin, a microarray surface, a chromatography support, and the like. In some instances, the support is selected from a particle, a planar solid substrate, a fibrous mesh, a hydrogel, a porous matrix, a pin, a microarray surface and a chromatography support. The support may be incorporated into a system that it provides for cell isolation assisted by any convenient methods, such as a manually-operated syringe, a centrifuge or an automated liquid handling system. In some cases, the support finds use in an automated liquid handling system for the high throughput isolation of cells, such as a flow cytometer.

In some embodiments of the method, the separating step includes applying an external magnetic field to immobilize a magnetic particle. Any convenient magnet may be used as a source of the external magnetic field (e.g., magnetic field gradient). In some cases, the external magnetic field is generated by a magnetic source, e.g. by a permanent magnet or electromagnet. In some cases, immobilizing the magnetic particles means the magnetic particles accumulate near the surface closest to the magnetic field gradient source, i.e. the magnet.

The separating may further include one or more optional washing steps to remove unbound material of the sample from the support. Any convenient washing methods may be used, e.g., washing the immobilized support with a biocompatible buffer which preserves the specific binding interaction of the polymeric dye and the specific binding member. Separation and optional washing of unbound material of the sample from the support provides for an enriched population of target cells where undesired cells and material may be removed.

In certain embodiments, the method further includes detecting the labelled target. Detecting the labelled target may include exciting the multichromophore with one or more lasers and subsequently detecting fluorescence emission from the polymeric dye using one or more optical detectors.

Also provided are methods of labelled a target molecule. The subject polymeric dyes, including tandem dyes, find use in a variety of methods of labelling, separation, detection and/or analysis. In some embodiments, the method includes: contacting the target molecule with a polymeric dye to produce a labelled target molecule, wherein the polymeric dye includes: a water soluble light harvesting multichromophore comprising a conjugated segment comprising: a fluorene co-monomer; and a UV absorbance-modifying co-monomer; wherein the multichromophore has an ultraviolet absorption maximum; and a conjugation tag that covalently links to the target molecule.

In some embodiments, the polymeric dye is a polymeric tandem dye. As such, in some cases, the polymeric dye further includes an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith. In certain instances, the polymeric dye is itself fluorescent. In some embodiments, the polymeric dye is described by formula (IX):

where:

F¹ is a fused 6-5-6 tricyclic co-monomer;

each M¹ and M² are each independently a UV absorbance-modifying co-monomer;

b is 1 or 2;

a, c, d, e and f are each independently 0 or 1, wherein a+c+d+f≥1;

L¹ is a linking co-monomer and Z¹ is a chemoselective tag or an acceptor chromophore;

n is an integer from 1 to 10,000;

m is 0 or an integer from 1 to 10,000;

p is an integer from 1 to 100,000; and

one of G¹ and G² is a terminal group and the other of G¹ and G² is the conjugation tag. In certain embodiments, Z¹ is the acceptor chromophore. In certain embodiments, Z¹ is a chemoselective tag. In certain cases, e is 0. In some instances of formula (X), F¹ is a fluorene co-monomer. In certain instances of formula (X), F¹ is a carbazole co-monomer.

As used herein the term “conjugation tag” refers to a group that includes a chemoselective functional group (e.g., as described herein) that can covalently link with a compatible functional group of a target molecule, after optional activation and/or deprotection. Any convenient conjugation tags may be utilized in the subject polymeric dyes in order to conjugate the dye to a target molecule of interest. In some embodiments, the conjugation tag includes a terminal functional group selected from an amino, a carboxylic acid or a derivative thereof, a thiol, a hydroxyl, a hydrazine, a hydrazide, a azide, an alkyne and a protein reactive group (e.g. amino-reactive, thiol-reactive, hydroxyl-reactive, imidazolyl-reactive or guanidinyl-reactive).

Any convenient methods and reagent may be adapted for use in the subject labelling methods in order to covalently link the conjugation tag to the target molecule. Methods of interest for labelling a target, include but are not limited to, those methods and reagents described by Hermanson, Bioconjugate Techniques, Third edition, Academic Press, 2013. The contacting step may be performed in an aqueous solution. In some instances, the conjugation tag includes an amino functional group and the target molecule includes an activated ester functional group, such as a NHS ester or sulfo-NHS ester, or vice versa. In certain instances, the conjugation tag includes a maleimide functional group and the target molecule includes a thiol functional group, or vice versa.

Any convenient target molecules may be selected for labelling utilizing the subject methods. Target molecules of interest include, but are not limited to, a nucleic acid, such as an RNA, DNA, PNA, CNA, HNA, LNA or ANA molecule, a protein, such as a fusion protein, a modified protein, such as a phosphorylated, glycosylated, ubiquitinated, SUMOylated, or acetylated protein, or an antibody, a peptide, an aggregated biomolecule, a cell, a small molecule, a vitamin and a drug molecule. As used herein, the term “a target protein” refers to all members of the target family, and fragments thereof. The target protein may be any protein of interest, such as a therapeutic or diagnostic target, including but not limited to: hormones, growth factors, receptors, enzymes, cytokines, osteoinductive factors, colony stimulating factors and immunoglobulins. The term “target protein” is intended to include recombinant and synthetic molecules, which can be prepared using any convenient recombinant expression methods or using any convenient synthetic methods, or purchased commercially. In some embodiments, the target molecule is a specific binding member (e.g., as described herein). In certain instances, the specific binding member is an antibody. In some instances, the specific binding member is an antibody fragment or binding derivative thereof. In some case, the antibody fragment or binding derivative thereof is selected from a Fab fragment, a F(ab′)₂ fragment, a scFv, a diabody and a triabody.

In some cases, the method includes a separating step where the labelled target molecule is separated from the reaction mixture, e.g., excess reagents or unlabeled target. A variety of methods may be utilized to separate a target from a sample, e.g., via immobilization on a support, precipitation, chromatography, and the like.

In some instances, the method further includes detecting and/or analyzing the labelled target molecule. In some instances, the method further includes fluorescently detecting the labelled target molecule. Any convenient methods may be utilized to detect and/or analyse the labelled target molecule in conjunction with the subject methods and compositions. Methods of analyzing a target of interest that find use in the subject methods, include but are not limited to, flow cytometry, in-situ hybridization, enzyme-linked immunosorbent assays (ELISAs), western blot analysis, magnetic cell separation assays and fluorochrome purification chromatography. Detection methods of interest include but are not limited to fluorescence spectroscopy, nucleic acid sequencing, fluorescence in-situ hybridization (FISH), protein mass spectroscopy, flow cytometry, and the like.

Detection may be achieved directly via a reporter molecule, or indirectly by a secondary detection system. The latter may be based on any one or a combination of several different principles including but not limited to, antibody labelled anti-species antibody and other forms of immunological or non-immunological bridging and signal amplification systems (e.g., biotin-streptavidin technology, protein-A and protein-G mediated technology, or nucleic acid probe/anti-nucleic acid probes, and the like). The label used for direct or indirect detection may be any detectable reported molecule. Suitable reporter molecules may be those known in the field of immunocytochemistry, molecular biology, light, fluorescence, and electron microscopy, cell immunophenotyping, cell sorting, flow cytometry, cell visualization, detection, enumeration, and/or signal output quantification. Labels of interest include, but are not limited to fluorophores, luminescent labels, metal complexes, radioisotopes, biotin, streptavidin, enzymes, or other detection labels and combination of labels such as enzymes and a luminogenic substrate. Enzymes of interest and their substrates include alkaline phosphatase, horseradish peroxidase, beta-galactosidase, and luciferase, and the like. More than one antibody of specific and/or non-specific nature might be labelled and used simultaneously or sequentially to enhance target detection, identification, and/or analysis. Labels of interest include, but are not limited to FITC (fluorescein isothiocyanate) AMCA (7-amino-4-methylcoumarin-3-acetic acid), Alexa Fluor 488, Alexa Fluor 594, Alexa Fluor 350, DyLight350, phycoerythrin, allophycocyanin and stains for detecting nuclei such as Hoechst 33342, LDS751, TO-PRO and DAPI.

Systems

Aspects of the invention further include systems for use in practicing the subject methods and compositions. A sample analysis system may include a flow channel loaded with a sample and a labelled specific binding member. In some embodiments, the system is a flow cytometric system including: a flow cytometer including a flow path; a composition in the flow path, wherein the composition includes: a sample; and a labelled specific binding member (e.g., as described herein). In some instances of the system, the labelled specific binding member includes: a water soluble light harvesting multichromophore including a conjugated segment comprising: a fused 6-5-6 tricyclic co-monomer; and a UV absorbance-modifying co-monomer; where the multichromophore has an ultraviolet absorption maximum; and a specific binding member that specifically binds a target analyte and is covalently linked to the multichromophore. The multichromophore may be a polymeric dye that is itself fluorescent. The multichromophore may be a polymeric tandem dye. In certain instances, the labelled specific binding member further includes an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith. In some embodiments, the labelled specific binding member is described by formula (X):

wherein:

F¹ is a fused 6-5-6 tricyclic co-monomer;

each M¹ and M² are each independently a UV absorbance-modifying co-monomer;

b is 1 or 2;

a, c, d, e and f are each independently 0 or 1, wherein a+c+d+f≥1;

L¹ is a linking co-monomer that is linked to —Z, wherein Z¹ is a chemoselective tag or an acceptor chromophore;

n is an integer from 1 to 10,000;

m is an integer from 1 to 10,000;

p is an integer from 1 to 100,000; and

one of G¹ and G² is a terminal group and the other of G¹ and G² is a linked specific binding member. In some instances of formula (XI), F¹ is a fluorene co-monomer. In certain instances of formula (XI), F¹ is a carbazole co-monomer.

In certain embodiments of the system, the composition further includes a second specific binding member that is support bound and specifically binds the target analyte. In some cases, the support includes a magnetic particle. As such, in certain instances, the system may also include a controllable external paramagnetic field configured for application to an assay region of the flow channel.

The sample may include a cell. In some instances, the sample is a cell-containing biological sample. In some instances, the sample includes a labelled specific binding member specifically bound to a target cell. In certain instances, the target analyte that is specifically bound by the specific binding member is a cell surface marker of the cell. In certain cases, the cell surface marker is selected from a cell receptor and a cell surface antigen.

In certain aspects, the system may also include a light source configured to direct light to an assay region of the flow channel. The system may include a detector configured to receive a signal from an assay region of the flow channel, wherein the signal is provided by the fluorescent composition. Optionally further, the sample analysis system may include one or more additional detectors and/or light sources for the detection of one or more additional signals.

In certain aspects, the system may further include computer-based systems configured to detect the presence of the fluorescent signal. A “computer-based system” refers to the hardware means, software means, and data storage means used to analyze the information of the present invention. The minimum hardware of the computer-based systems of the present invention includes a central processing unit (CPU), input means, output means, and data storage means. A skilled artisan can readily appreciate that any one of the currently available computer-based system are suitable for use in the subject systems. The data storage means may include any manufacture including a recording of the present information as described above, or a memory access means that can access such a manufacture.

To “record” data, programming or other information on a computer readable medium refers to a process for storing information, using any such methods as known in the art. Any convenient data storage structure may be chosen, based on the means used to access the stored information. A variety of data processor programs and formats can be used for storage, e.g., word processing text file, database format, etc.

A “processor” references any hardware and/or software combination that will perform the functions required of it. For example, any processor herein may be a programmable digital microprocessor such as available in the form of an electronic controller, mainframe, server or personal computer (desktop or portable). Where the processor is programmable, suitable programming can be communicated from a remote location to the processor, or previously saved in a computer program product (such as a portable or fixed computer readable storage medium, whether magnetic, optical or solid state device based). For example, a magnetic medium or optical disk may carry the programming, and can be read by a suitable reader communicating with each processor at its corresponding station.

In addition to the sensor device and signal processing module, e.g., as described above, systems of the invention may include a number of additional components, such as data output devices, e.g., monitors and/or speakers, data input devices, e.g., interface ports, keyboards, etc., fluid handling components, power sources, etc.

In certain aspects, the system includes a flow cytometer. Flow cytometers of interest include, but are not limited, to those devices described in U.S. Pat. Nos. 4,704,891; 4,727,029; 4,745,285; 4,867,908; 5,342,790; 5,620,842; 5,627,037; 5,701,012; 5,895,922; and 6,287,791; the disclosures of which are herein incorporated by reference.

Other systems may find use in practicing the subject methods. In certain aspects, the system may be a fluorimeter or microscope loaded with a sample having a fluorescent composition of any of the embodiments discussed herein. The fluorimeter or microscope may include a light source configured to direct light to the assay region of the flow channel. The fluorimeter or microscope may also include a detector configured to receive a signal from an assay region of the flow channel, wherein the signal is provided by the fluorescent composition.

Kits

Aspects of the invention further include kits for use in practicing the subject methods and compositions. The compositions of the invention can be included as reagents in kits either as starting materials or provided for use in, for example, the methodologies described above.

A kit may include a water soluble light harvesting multichromophore including a conjugated segment including: a fused 6-5-6 tricyclic co-monomer; and a UV absorbance-modifying co-monomer, wherein the multichromophore has an ultraviolet absorption maximum; and one or more components selected from a polymeric tandem dye, a fluorophore, a specific binding member, a specific binding member conjugate, a support bound specific binding member, a cell, a support, a biocompatible aqueous elution buffer, and instructions for use. In some embodiments of the kit, the multichromophore is covalently linked to a specific binding member. In some instances, the specific binding member is an antibody. In certain instances, the specific binding member is an antibody fragment or binding derivative thereof. In certain cases, the antibody fragment or binding derivative thereof is selected from a Fab fragment, a F(ab′)2 fragment, a scFv, a diabody and a triabody. The multichromophore may be a polymeric dye that is itself fluorescent. The multichromophore may be a polymeric tandem dye. In some cases, the multichromophore further includes an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith.

In certain embodiments, the kit finds use in evaluating a sample for the presence of a target analyte, such as an intracellular target. As such, in some instances, the kit includes one or more components suitable for lysing cells. The one or more additional components of the kit may be provided in separate containers (e.g., separate tubes, bottles, or wells in a multi-well strip or plate).

In certain aspects, the kit further includes reagents for performing a flow cytometric assay. Reagents of interest include, but are not limited to, buffers for reconstitution and dilution, buffers for contacting a cell sample the multichromophore, wash buffers, control cells, control beads, fluorescent beads for flow cytometer calibration and combinations thereof. The kit may also include one or more cell fixing reagents such as paraformaldehyde, glutaraldehyde, methanol, acetone, formalin, or any combinations or buffers thereof. Further, the kit may include a cell permeabilizing reagent, such as methanol, acetone or a detergent (e.g., triton, NP-40, saponin, tween 20, digitonin, leucoperm, or any combinations or buffers thereof. Other protein transport inhibitors, cell fixing reagents and cell permeabilizing reagents familiar to the skilled artisan are within the scope of the subject kits.

The compositions of the kit may be provided in a liquid composition, such as any suitable buffer. Alternatively, the compositions of the kit may be provided in a dry composition (e.g., may be lyophilized), and the kit may optionally include one or more buffers for reconstituting the dry composition. In certain aspects, the kit may include aliquots of the compositions provided in separate containers (e.g., separate tubes, bottles, or wells in a multi-well strip or plate).

In addition, one or more components may be combined into a single container, e.g., a glass or plastic vial, tube or bottle. In certain instances, the kit may further include a container (e.g., such as a box, a bag, an insulated container, a bottle, tube, etc.) in which all of the components (and their separate containers) are present. The kit may further include packaging that is separate from or attached to the kit container and upon which is printed information about the kit, the components of the and/or instructions for use of the kit.

In addition to the above components, the subject kits may further include instructions for practicing the subject methods. These instructions may be present in the subject kits in a variety of forms, one or more of which may be present in the kit. One form in which these instructions may be present is as printed information on a suitable medium or substrate, e.g., a piece or pieces of paper on which the information is printed, in the packaging of the kit, in a package insert, etc. Yet another means would be a computer readable medium, e.g., diskette, CD, DVD, portable flash drive, etc., on which the information has been recorded. Yet another means that may be present is a website address which may be used via the Internet to access the information at a removed site. Any convenient means may be present in the kits.

Utility

The compositions, methods and systems as described herein may find use in a variety of applications, including diagnostic and research applications, in which the labelling detection and/or analysis of a target of interest is desirable. Such applications include methodologies such as cytometry, microscopy, immunoassays (e.g. competitive or non-competitive), assessment of a free analyte, assessment of receptor bound ligand, and so forth. The compositions, system and methods described herein may be useful in analysis of any of a number of samples, including but not limited to, biological fluids, cell culture samples, and tissue samples. In certain aspects, the compositions, system and methods described herein may find use in methods where analytes are detected in a sample, if present, using fluorescent labels, such as in fluorescent activated cell sorting or analysis, immunoassays, immunostaining, and the like. In certain instances, the compositions and methods find use in applications where the evaluation of a sample for the presence of a target analyte is of interest.

In some cases, the methods and compositions find use in any assay format where the detection and/or analysis of a target from a sample is of interest, including but not limited to, flow cytometry, in-situ hybridization, enzyme-linked immunosorbent assays (ELISAs), western blot analysis, magnetic cell separation assays and fluorochrome purification chromatography. In certain instances, the methods and compositions find use in any application where the fluorescent labelling of a target molecule is of interest. The subject compositions may be adapted for use in any convenient applications where pairs of specific binding members find use, such as biotin-streptavidin and hapten-anti-hapten antibody.

The following examples are offered by way of illustration and not by way of limitation.

EXPERIMENTAL Example 1

A series of tandem dyes were prepared based on a core Structure 1 depicted below including a series of linked fluorophores. FIG. 1 illustrates the fluorescence emission profiles of a variety of polymeric tandem dyes based on the multichromophore core structure 1 linked to a variety of different acceptor chromophores.

where the Dye is Dyomics dyes DY 431, DY 485XL, DY 610, DY 640, Cy3, Cy 3.5 or diethylamino coumarin (DEAC).

A second series of UV absorbing polymeric dyes were prepared and characterized. FIG. 2 illustrates the UV absorption spectra of a variety of multichromophores of interest, MC-1 to MC-5.

Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it is readily apparent to those of ordinary skill in the art in light of the teachings of this invention that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

Accordingly, the preceding merely illustrates the principles of the invention. It will be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended to aid the reader in understanding the principles of the invention and the concepts contributed by the inventors to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the invention as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents and equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. The scope of the present invention, therefore, is not intended to be limited to the exemplary embodiments shown and described herein. Rather, the scope and spirit of present invention is embodied by the following. 

What is claimed is:
 1. A light harvesting multichromophore comprising a conjugated segment comprising: a fused 6-5-6 tricyclic co-monomer; and a UV absorbance-modifying co-monomer; wherein the multichromophore has an ultraviolet absorption maximum.
 2. The multichromophore according to claim 1, wherein the multichromophore has an absorption maximum wavelength in the range of 300 to 400 nm and an emission maximum wavelength in the range of 375 to 900 nm.
 3. The multichromophore according to claim 1, wherein: the multichromophore comprises 25% or more by molarity of the UV absorbance-modifying co-monomer; and the multichromophore is a conjugated polymer comprising 5 or more monomeric repeat units.
 4. The multichromophore according to claim 1, wherein the multichromophore has a molar extinction coefficient of 5×10⁵ M⁻¹cm⁻¹ or more.
 5. The multichromophore according to claim 1, wherein the multichromophore has a quantum yield of 0.3 or more.
 6. The multichromophore according to claim 1, wherein the multichromophore is described by formula (I):

wherein: F¹ is a fused 6-5-6 tricyclic co-monomer; each M¹ and M² are each independently a UV absorbance-modifying co-monomer; b is 1 or 2; a, c, d, e and f are each independently 0 or 1, wherein a+c+d+f≥1; L¹ is a linking co-monomer comprising a chemoselective tag —Z¹; n is an integer from 1 to 10,000; m is 0 or an integer from 1 to 10,000; p is an integer from 1 to 100,000; and G¹ and G² are each independently selected from the group consisting of a terminal group, a π conjugated segment, a linker and a linked specific binding member.
 7. The multichromophore according to claim 6, wherein the multichromophore is described by formula (II):


8. The multichromophore according to claim 6, wherein the multichromophore is described by formula (III):


9. The multichromophore according to claim 6, wherein the multichromophore is described by formula (IV):


10. A method of evaluating a sample for the presence of a target analyte, the method comprising: (a) contacting the sample with a polymeric dye conjugate that specifically binds the target analyte to produce a labelling composition contacted sample, wherein the polymeric dye conjugate comprises: (i) a light harvesting multichromophore comprising a repeat unit comprising: a fused 6-5-6 tricyclic co-monomer; and a UV absorbance-modifying co-monomer that is a substituted aryl co-monomer or a substituted or unsubstituted heteroaryl co-monomer; and (ii) a specific binding member covalently linked to the multichromophore; and (b) assaying the labelling composition contacted sample for the presence of a polymeric dye conjugate-target analyte binding complex to evaluate whether the target analyte is present in the sample.
 11. The method according to claim 10, wherein the polymeric dye conjugate further comprises an acceptor chromophore covalently linked to the multichromophore in energy-receiving proximity therewith.
 12. The method according to claim 10, wherein the acceptor chromophore is selected from cyanine dye, xanthene dye, coumarin dye, thiazine dye and acridine dye.
 13. The method according to claim 10, wherein the fused 6-5-6 tricyclic co-monomer comprises a central 5-membered ring that is a heterocycle.
 14. The method according to claim 13, wherein the fused 6-5-6 tricyclic co-monomer is a carbazole co-monomer.
 15. The method according to claim 10, wherein the fused 6-5-6 tricyclic co-monomer is a fluorene co-monomer linked via positions 2 and 7 to a polymer backbone.
 16. The method according to claim 10, wherein the fused 6-5-6 tricyclic co-monomer is a fluorene co-monomer linked via positions 3 and 6 to a polymer backbone.
 17. The method according to claim 16, wherein the fused 6-5-6 tricyclic co-monomer is of the structure:

wherein: Z is —C(R¹)₂ ⁻¹ Or —N(R¹)—; each R is H; and each R¹ is independently selected from alkyl, substituted alkyl, aralkyl, substituted aralkyl, PEG moiety, and -L¹-Z¹, where L¹ is a linker and Z¹ is a chemoselective tag.
 18. The method according to claim 17, wherein each R¹ is substituted alkyl or substituted aralkyl.
 19. The method according to claim 10, wherein the UV absorbance-modifying co-monomer is selected from substituted 1,4-phenyl, substituted 1,3-phenyl, substituted or unsubstituted 2,5-pyridyl, and substituted or unsubstituted 2,6-pyridyl.
 20. The method according to claim 10, wherein the UV absorbance-modifying co-monomer is selected from one of the following:

wherein: Z²-Z⁵ are each independently CR or N, wherein at least one Z²-Z⁵ is N; and each R and R¹¹—R¹⁶ are independently selected from the group consisting of hydrogen, halogen, cyano, alkoxy, substituted alkoxy, alkyl and substituted alkyl. 